IDEAS home Printed from https://ideas.repec.org/p/dia/wpaper/dt201519.html
   My bibliography  Save this paper

Cognitive, Non-Cognitive Skills and Gender Wage Gaps: Evidence from Linked Employer-Employee Data in Bangladesh

Author

Listed:
  • Christophe Nordman

    (IRD, UMR 225 DIAL, PSL, Université Paris Dauphine, LEDa)

  • Leopold R. Sarr

    (The World Bank, South Asia Human Development Unit, Washington DC, USA)

  • Smriti Sharma

    (UNU-WIDER, Helsinki, Finland)

Abstract

(english) We use a first-hand linked employer-employee dataset representing the formal sector of Bangladesh to explain gender wage gaps by the inclusion of measures of cognitive skills and personality traits. Our results show that while cognitive skills are important in determining mean wages, personality traits have little explanatory power. However, quantile regressions indicate that personality traits do matter in certain parts of the conditional wage distribution, especially for wages of females. Cognitive skills as measured by reading and numeracy also confer different benefits across the wage distribution to females and males respectively. Quantile decompositions indicate that these skills and traits reduce the unexplained gender gap, mainly in the upper parts of the wage distribution. Finally, results suggest that employers place greater consideration on observables such as academic background and prior work experience, and may also make assumptions about the existence of sex-specific skills of their workers, which could then widen the within-firm gender wage gap. _________________________________ (français) A partir de données liées employeurs-employés de première main couvrant le secteur formel du Bangladesh, nous expliquons l'écart salarial de genre en introduisant des mesures des compétences cognitives et des traits de personnalité des employés. Tandis que les compétences cognitives s'avèrent être d'importants déterminants des salaires lorsque ceux-ci sont observés au point moyen, les traits de personnalité présentent en revanche à ce niveau peu de pouvoir explicatif. Néanmoins, l'emploi de régressions quantiles sur les salaires indiquent que ces traits de personnalité jouent à certains endroits de la distribution conditionnelle, en particulier lorsqu'il s'agit des salaires des femmes. Les compétences cognitives, approchées par des scores en lecture et en calcul des salariés, montrent elles aussi des effets différenciés selon le sexe le long de la distribution des salaires. Des décompositions en quantile indiquent ensuite que ces compétences et traits de personnalité réduisent la part inexpliquée de l'écart salarial de genre, et ce principalement dans la partie haute de la distribution des salaires. Enfin, les résultats suggèrent que les employeurs privilégieraient davantage dans leurs pratiques de recrutement et politique salariale l'acquis scolaire et l’expérience professionnelle antérieure. Ils ont aussi tendance à faire usage de stéréotypes sur l'existence de compétences spécifiques selon le sexe des salariés, ce qui a tendance à creuser l'écart salarial de genre au sein même de l'entreprise.

Suggested Citation

  • Christophe Nordman & Leopold R. Sarr & Smriti Sharma, 2015. "Cognitive, Non-Cognitive Skills and Gender Wage Gaps: Evidence from Linked Employer-Employee Data in Bangladesh," Working Papers DT/2015/19, DIAL (Développement, Institutions et Mondialisation).
    • Handle: RePEc:dia:wpaper:dt201519
    as

    Download full text from publisher

    File URL: https://dial.ird.fr/wp-content/uploads/2021/10/2015-19-Cognitive-Non-Cognitive-Skills-and-Gender-Wage-Gaps-Evidence-from-Linked-Employer-Employee-Data-in-Bangladesh.pdf
    File Function: First version, 2015
    Download Restriction: no
    ---><---

    Other versions of this item:

    References listed on IDEAS

    as
    1. Erik Hanushek & Stephen Machin & Ludger Woessmann (ed.), 2011. "Handbook of the Economics of Education," Handbook of the Economics of Education, Elsevier, edition 1, volume 4, number 4, June.
    2. Bertrand, Marianne, 2011. "New Perspectives on Gender," Handbook of Labor Economics, in: O. Ashenfelter & D. Card (ed.), Handbook of Labor Economics, edition 1, volume 4, chapter 17, pages 1543-1590, Elsevier.
    3. William J. Carrington & Kenneth R. Troske, 1995. "Gender Segregation in Small Firms," Journal of Human Resources, University of Wisconsin Press, vol. 30(3), pages 503-533.
    4. Cobb-Clark, Deborah A. & Tan, Michelle, 2011. "Noncognitive skills, occupational attainment, and relative wages," Labour Economics, Elsevier, vol. 18(1), pages 1-13, January.
    5. O. Ashenfelter & D. Card (ed.), 2011. "Handbook of Labor Economics," Handbook of Labor Economics, Elsevier, edition 1, volume 4, number 4.
    6. O. Ashenfelter & D. Card (ed.), 2011. "Handbook of Labor Economics," Handbook of Labor Economics, Elsevier, edition 1, volume 4, number 5.
    7. Geeta Gandhi Kingdon & Jeemol Unni, 2001. "Education and Women's Labour Market Outcomes in India," Education Economics, Taylor & Francis Journals, vol. 9(2), pages 173-195.
    8. Lex Borghans & Angela Lee Duckworth & James J. Heckman & Bas ter Weel, 2008. "The Economics and Psychology of Personality Traits," Journal of Human Resources, University of Wisconsin Press, vol. 43(4).
    9. Appleton, Simon & Hoddinott, John & Krishnan, Pramila, 1999. "The Gender Wage Gap in Three African Countries," Economic Development and Cultural Change, University of Chicago Press, vol. 47(2), pages 289-312, January.
    10. Heckman, James J. & Kautz, Tim, 2012. "Hard evidence on soft skills," Labour Economics, Elsevier, vol. 19(4), pages 451-464.
    11. Shantanu Khanna, 2012. "Gender wage discrimination in India-- Glass ceiling or sticky floor?," Working papers 214, Centre for Development Economics, Delhi School of Economics.
    12. Ivan A. Canay, 2011. "A simple approach to quantile regression for panel data," Econometrics Journal, Royal Economic Society, vol. 14(3), pages 368-386, October.
    13. Oaxaca, Ronald, 1973. "Male-Female Wage Differentials in Urban Labor Markets," International Economic Review, Department of Economics, University of Pennsylvania and Osaka University Institute of Social and Economic Research Association, vol. 14(3), pages 693-709, October.
    14. Herbert Gintis & Samuel Bowles & Melissa Osborne, 2001. "Incentive-Enhancing Preferences: Personality, Behavior, and Earnings," American Economic Review, American Economic Association, vol. 91(2), pages 155-158, May.
    15. Christophe J. Nordman & François Roubaud, 2009. "Reassessing the Gender Wage Gap in Madagascar: Does Labor Force Attachment Really Matter?," Economic Development and Cultural Change, University of Chicago Press, vol. 57(4), pages 785-808, July.
    16. repec:dau:papers:123456789/4305 is not listed on IDEAS
    17. Mohamed Jellal & Christophe Nordman & Francois-Charles Wolff, 2008. "Evidence on the glass ceiling effect in France using matched worker-firm data," Applied Economics, Taylor & Francis Journals, vol. 40(24), pages 3233-3250.
    18. Geeta Gandhi Kingdon, 1998. "Does the labour market explain lower female schooling in India?," Journal of Development Studies, Taylor & Francis Journals, vol. 35(1), pages 39-65.
    19. Heath, Rachel & Mushfiq Mobarak, A., 2015. "Manufacturing growth and the lives of Bangladeshi women," Journal of Development Economics, Elsevier, vol. 115(C), pages 1-15.
    20. Cobb-Clark, Deborah A. & Schurer, Stefanie, 2012. "The stability of big-five personality traits," Economics Letters, Elsevier, vol. 115(1), pages 11-15.
    21. James J. Heckman & Jora Stixrud & Sergio Urzua, 2006. "The Effects of Cognitive and Noncognitive Abilities on Labor Market Outcomes and Social Behavior," Journal of Labor Economics, University of Chicago Press, vol. 24(3), pages 411-482, July.
    22. Muriel Niederle & Lise Vesterlund, 2007. "Do Women Shy Away From Competition? Do Men Compete Too Much?," The Quarterly Journal of Economics, President and Fellows of Harvard College, vol. 122(3), pages 1067-1101.
    23. Alan S. Blinder, 1973. "Wage Discrimination: Reduced Form and Structural Estimates," Journal of Human Resources, University of Wisconsin Press, vol. 8(4), pages 436-455.
    24. José Mata & José A. F. Machado, 2005. "Counterfactual decomposition of changes in wage distributions using quantile regression," Journal of Applied Econometrics, John Wiley & Sons, Ltd., vol. 20(4), pages 445-465.
    25. Almlund, Mathilde & Duckworth, Angela Lee & Heckman, James & Kautz, Tim, 2011. "Personality Psychology and Economics," Handbook of the Economics of Education, in: Erik Hanushek & Stephen Machin & Ludger Woessmann (ed.), Handbook of the Economics of Education, edition 1, volume 4, chapter 0, pages 1-181, Elsevier.
    26. Jeffrey A. Flory & Andreas Leibbrandt & John A. List, 2015. "Do Competitive Workplaces Deter Female Workers? A Large-Scale Natural Field Experiment on Job Entry Decisions," The Review of Economic Studies, Review of Economic Studies Ltd, vol. 82(1), pages 122-155.
    27. Deborah A. Cobb‐Clark & Stefanie Schurer, 2013. "Two Economists' Musings on the Stability of Locus of Control," Economic Journal, Royal Economic Society, vol. 0, pages 358-400, August.
    28. Marcel Fafchamps & Mans Söderbom & Najy Benhassine, 2009. "Wage Gaps and Job Sorting in African Manufacturing," Journal of African Economies, Centre for the Study of African Economies, vol. 18(5), pages 824-868, November.
    29. repec:dau:papers:123456789/4377 is not listed on IDEAS
    30. Glewwe, Paul & Huang, Qiuqiong & Park, Albert, 2011. "Cognitive Skills, Non-Cognitive Skills, and the Employment and Wages of Young Adults in Rural China," 2011 Annual Meeting, July 24-26, 2011, Pittsburgh, Pennsylvania 103407, Agricultural and Applied Economics Association.
    31. Card, David & Cardoso, Ana Rute & Kline, Patrick, 2013. "Bargaining and the Gender Wage Gap: A Direct Assessment," IZA Discussion Papers 7592, Institute of Labor Economics (IZA).
    32. James Albrecht & Anders Bjorklund & Susan Vroman, 2003. "Is There a Glass Ceiling in Sweden?," Journal of Labor Economics, University of Chicago Press, vol. 21(1), pages 145-177, January.
    33. Christophe J. Nordman & François-Charles Wolff, 2009. "Is There a Glass Ceiling in Morocco? Evidence from Matched Worker--Firm Data," Journal of African Economies, Centre for the Study of African Economies, vol. 18(4), pages 592-633, August.
    34. Lundberg, Shelly J & Startz, Richard, 1983. "Private Discrimination and Social Intervention in Competitive Labor Markets," American Economic Review, American Economic Association, vol. 73(3), pages 340-347, June.
    35. Mohammad Niaz Asadullah, 2006. "Returns to Education in Bangladesh," Education Economics, Taylor & Francis Journals, vol. 14(4), pages 453-468.
    36. Dickerson, Andy & McIntosh, Steven & Valente, Christine, 2015. "Do the maths: An analysis of the gender gap in mathematics in Africa," Economics of Education Review, Elsevier, vol. 46(C), pages 1-22.
    37. Chi, Wei & Li, Bo, 2008. "Glass ceiling or sticky floor? Examining the gender earnings differential across the earnings distribution in urban China, 1987-2004," Journal of Comparative Economics, Elsevier, vol. 36(2), pages 243-263, June.
    38. Nils Braakmann, 2009. "The Role of Psychological Traits for the Gender Gap in Full-Time Employment and Wages: Evidence from Germany," SOEPpapers on Multidisciplinary Panel Data Research 162, DIW Berlin, The German Socio-Economic Panel (SOEP).
    39. David Neumark, 1988. "Employers' Discriminatory Behavior and the Estimation of Wage Discrimination," Journal of Human Resources, University of Wisconsin Press, vol. 23(3), pages 279-295.
    40. Rachel Croson & Uri Gneezy, 2009. "Gender Differences in Preferences," Journal of Economic Literature, American Economic Association, vol. 47(2), pages 448-474, June.
    41. Pham, Thai-Hung & Reilly, Barry, 2007. "The gender pay gap in Vietnam, 1993-2002: A quantile regression approach," Journal of Asian Economics, Elsevier, vol. 18(5), pages 775-808, October.
    42. Nyhus, Ellen K. & Pons, Empar, 2005. "The effects of personality on earnings," Journal of Economic Psychology, Elsevier, vol. 26(3), pages 363-384, June.
    43. Christophe Nordman & François-Charles Wolff, 2008. "Islands through the glass ceiling? Evidence of gender wage gaps in Madagascar and Mauritius," Working Papers DT/2008/02, DIAL (Développement, Institutions et Mondialisation).
    44. Salma Ahmed & Pushkar Maitra, 2015. "A Distributional Analysis of the Gender Wage Gap in Bangladesh," Journal of Development Studies, Taylor & Francis Journals, vol. 51(11), pages 1444-1458, November.
    45. repec:dau:papers:123456789/4344 is not listed on IDEAS
    46. Erik Lindqvist & Roine Vestman, 2011. "The Labor Market Returns to Cognitive and Noncognitive Ability: Evidence from the Swedish Enlistment," American Economic Journal: Applied Economics, American Economic Association, vol. 3(1), pages 101-128, January.
    47. Nicole M. Fortin, 2008. "The Gender Wage Gap among Young Adults in the United States: The Importance of Money versus People," Journal of Human Resources, University of Wisconsin Press, vol. 43(4).
    48. Paul Carrillo & Néstor Gandelman & Virginia Robano, 2014. "Sticky floors and glass ceilings in Latin America," The Journal of Economic Inequality, Springer;Society for the Study of Economic Inequality, vol. 12(3), pages 339-361, September.
    49. repec:dau:papers:123456789/4400 is not listed on IDEAS
    50. James J. Heckman & John Eric Humphries & Sergio Urzua & Gregory Veramendi, 2010. "The effects of educational choices on labor market, health, and social outcomes," Working Papers 2011-002, Human Capital and Economic Opportunity Working Group.
    51. Mohammad Niaz Asadullah (SKOPE, Department of Economics), "undated". "Returns to Education in Bangladesh," QEH Working Papers qehwps130, Queen Elizabeth House, University of Oxford.
    52. Semykina, Anastasia & Linz, Susan J., 2007. "Gender differences in personality and earnings: Evidence from Russia," Journal of Economic Psychology, Elsevier, vol. 28(3), pages 387-410, June.
    53. Nordman, Christophe J. & Robilliard, Anne-Sophie & Roubaud, François, 2011. "Gender and ethnic earnings gaps in seven West African cities," Labour Economics, Elsevier, vol. 18(S1), pages 132-145.
    54. Nils Braakmann, 2009. "Psychological traits and the gender gap in full-time employment and wages: Evidence from Germany," Working Paper Series in Economics 112, University of Lüneburg, Institute of Economics.
    55. Salma Ahmed & Pushkar Maitra, 2010. "Gender Wage Discrimination in Rural and Urban Labour Markets of Bangladesh," Oxford Development Studies, Taylor & Francis Journals, vol. 38(1), pages 83-112.
    56. Jeffrey A. Flory & Andreas Leibbrandt & John A. List, 2010. "Do Competitive Work Places Deter Female Workers? A Large-Scale Natural Field Experiment on Gender Differences in Job-Entry Decisions," NBER Working Papers 16546, National Bureau of Economic Research, Inc.
    57. Kuepie, Mathias & Nordman, Christophe J. & Roubaud, François, 2009. "Education and earnings in urban West Africa," Journal of Comparative Economics, Elsevier, vol. 37(3), pages 491-515, September.
    58. Meng, Xin, 2004. "Gender earnings gap: the role of firm specific effects," Labour Economics, Elsevier, vol. 11(5), pages 555-573, October.
    59. Gerrit Mueller & Erik Plug, 2006. "Estimating the Effect of Personality on Male and Female Earnings," ILR Review, Cornell University, ILR School, vol. 60(1), pages 3-22, October.
    Full references (including those not matched with items on IDEAS)

    Citations

    Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.
    as


    Cited by:

    1. Anne Hilger & Christophe Jalil Nordman & Leopold R. Sarr, 2018. "Cognitive and non-cognitive skills, hiring channels, and wages in Bangladesh," Working Papers DT/2018/11, DIAL (Développement, Institutions et Mondialisation).
    2. Ashwini Deshpande & Smriti Sharma, 2016. "Disadvantage and discrimination in self-employment: caste gaps in earnings in Indian small businesses," Small Business Economics, Springer, vol. 46(2), pages 325-346, February.
    3. Giulia La Mattina & Gabriel Picone & Alban Ahoure & Jose Carlos Kimou, 2017. "Female leaders and gender gaps within the firm: Evidence from three sub-Saharan African countries," WIDER Working Paper Series 063, World Institute for Development Economic Research (UNU-WIDER).
    4. Maksimova, Mariia, 2019. "The return to non-cognitive skills on the Russian labor market," Applied Econometrics, Russian Presidential Academy of National Economy and Public Administration (RANEPA), vol. 53, pages 55-72.
    5. Giulia La Mattina & Gabriel Picone & Alban Ahoure & Jose Carlos Kimou, 2017. "Female leaders and gender gaps within the firm: Evidence from three sub-Saharan African countries," WIDER Working Paper Series wp-2017-63, World Institute for Development Economic Research (UNU-WIDER).
    6. Rami Galal & Mona Said & Susan Joekes & Mina Sami, 2018. "Gender Diversity, Productivity, and Wages in Egyptian Firms," Working Papers 1207, Economic Research Forum, revised 12 Jun 2018.

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Christophe J Nordman & Leopold R Sarr & Smriti Sharma, 2019. "Skills, personality traits, and gender wage gaps: evidence from Bangladesh," Oxford Economic Papers, Oxford University Press, vol. 71(3), pages 687-708.
    2. Christophe J Nordman & Leopold R Sarr & Smriti Sharma, 2019. "Skills, personality traits, and gender wage gaps: evidence from Bangladesh," Oxford Economic Papers, Oxford University Press, vol. 71(3), pages 687-708.
    3. Leonora Risse & Lisa Farrell & Tim R L Fry, 2018. "Personality and pay: do gender gaps in confidence explain gender gaps in wages?," Oxford Economic Papers, Oxford University Press, vol. 70(4), pages 919-949.
    4. Brenzel, Hanna & Laible, Marie-Christine, 2016. "Does personality matter? : the impact of the big five on the migrant and gender wage gaps," IAB-Discussion Paper 201626, Institut für Arbeitsmarkt- und Berufsforschung (IAB), Nürnberg [Institute for Employment Research, Nuremberg, Germany].
    5. Ksenia V. Rozhkova & Natalya Yemelina & Sergey Yu. Roshchin, 2021. "Can Non-Cognitive Skills Explain The Gender Wage Gap In Russia? An Unconditional Quantile Regression Approach," HSE Working papers WP BRP 252/EC/2021, National Research University Higher School of Economics.
    6. Collischon & Matthias, 2018. "Can Personality Traits Explain Glass Ceilings?," SOEPpapers on Multidisciplinary Panel Data Research 965, DIW Berlin, The German Socio-Economic Panel (SOEP).
    7. Chen, Weiwei & Grove, Wayne A. & Hussey, Andrew, 2017. "The role of confidence and noncognitive skills for post-baccalaureate academic and labor market outcomes," Journal of Economic Behavior & Organization, Elsevier, vol. 138(C), pages 10-29.
    8. Hilger, Anne & Nordman, Christophe Jalil & Sarr, Leopold, 2018. "Cognitive and Non-Cognitive Skills, Hiring Channels, and Wages in Bangladesh," IZA Discussion Papers 11578, Institute of Labor Economics (IZA).
    9. Zheng Fang & Chris Sakellariou, 2015. "Glass Ceilings versus Sticky Floors: Evidence from Southeast Asia and an International Update," Asian Economic Journal, East Asian Economic Association, vol. 29(3), pages 215-242, September.
    10. Maria Cubel & Ana Nuevo‐Chiquero & Santiago Sanchez‐Pages & Marian Vidal‐Fernandez, 2016. "Do Personality Traits Affect Productivity? Evidence from the Laboratory," Economic Journal, Royal Economic Society, vol. 0(592), pages 654-681, May.
    11. Alita Nandi & Cheti Nicoletti, 2014. "Explaining personality pay gaps in the UK," Applied Economics, Taylor & Francis Journals, vol. 46(26), pages 3131-3150, September.
    12. Bonaccolto-Töpfer, Marina & Briel, Stephanie, 2022. "The gender pay gap revisited: Does machine learning offer new insights?," Labour Economics, Elsevier, vol. 78(C).
    13. Flinn, Christopher J. & Todd, Petra E & Zhang, Weilong, 2018. "Personality traits, intra-household allocation and the gender wage gap," European Economic Review, Elsevier, vol. 109(C), pages 191-220.
    14. Brieland, Stephanie & Töpfer, Marina, 2020. "The gender pay gap revisited: Does machine learning offer new insights?," Discussion Papers 111, Friedrich-Alexander University Erlangen-Nuremberg, Chair of Labour and Regional Economics.
    15. Sonja C. Kassenboehmer & Mathias G. Sinning, 2014. "Distributional Changes in the Gender Wage Gap," ILR Review, Cornell University, ILR School, vol. 67(2), pages 335-361, April.
    16. Glewwe, Paul & Song, Yang & Zou, Xianqiang, 2022. "Labor market outcomes, cognitive skills, and noncognitive skills in rural China," Journal of Economic Behavior & Organization, Elsevier, vol. 193(C), pages 294-311.
    17. Gensowski, Miriam & Gørtz, Mette & Schurer, Stefanie, 2021. "Inequality in personality over the life cycle," Journal of Economic Behavior & Organization, Elsevier, vol. 184(C), pages 46-77.
    18. Francine D. Blau & Lawrence M. Kahn, 2017. "The Gender Wage Gap: Extent, Trends, and Explanations," Journal of Economic Literature, American Economic Association, vol. 55(3), pages 789-865, September.
    19. Cobb-Clark, Deborah A. & Tan, Michelle, 2011. "Noncognitive skills, occupational attainment, and relative wages," Labour Economics, Elsevier, vol. 18(1), pages 1-13, January.
    20. Engelhardt, Carina, 2017. "Unemployment and personality: Are conscientiousness and agreeableness related to employability?," Hannover Economic Papers (HEP) dp-621, Leibniz Universität Hannover, Wirtschaftswissenschaftliche Fakultät.

    More about this item

    Keywords

    gender wage gap; cognitive skills; personality traits; matched worker-firm data; quantile decompositions; Bangladesh;
    All these keywords.

    JEL classification:

    • J16 - Labor and Demographic Economics - - Demographic Economics - - - Economics of Gender; Non-labor Discrimination
    • J24 - Labor and Demographic Economics - - Demand and Supply of Labor - - - Human Capital; Skills; Occupational Choice; Labor Productivity
    • J31 - Labor and Demographic Economics - - Wages, Compensation, and Labor Costs - - - Wage Level and Structure; Wage Differentials
    • J71 - Labor and Demographic Economics - - Labor Discrimination - - - Hiring and Firing
    • C21 - Mathematical and Quantitative Methods - - Single Equation Models; Single Variables - - - Cross-Sectional Models; Spatial Models; Treatment Effect Models
    • O12 - Economic Development, Innovation, Technological Change, and Growth - - Economic Development - - - Microeconomic Analyses of Economic Development

    NEP fields

    This paper has been announced in the following NEP Reports:

    Statistics

    Access and download statistics

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:dia:wpaper:dt201519. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: Loic Le Pezennec (email available below). General contact details of provider: https://edirc.repec.org/data/diallfr.html .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.