1979 · John W. Cosgriff, John M. Zawiskie · University of the Witwatersrand, Johannesburg Institutional Repository on DSpace (University of the Witwatersrand, Johannesburg) · 43
1975 · Susan Chernin, John W. Cosgriff · University of the Witwatersrand, Johannesburg Institutional Repository on DSpace (University of the Witwatersrand, Johannesburg) · 15