T. Wansbeek, und J. Buyze. Research Report BPA, 13593-81-M1. Department for Statistical Methods, Central Bureau of Statistics, Voorburg, The Netherlands, (1981)
C. Veldscholte, G. Antonides, und P. Kroonenberg. Research Report, R9519/A. Rotterdam Institute for Business Economic Studies, Erasmus University, Rotterdam, The Netherlands, (1995)
H. Triandis, R. Malpass, und J. Feldman. Variations in black and white perceptions of the social environment., University of Illinois Press, Urbana IL, (1976)