His dissertation , entitled Die kombinatorische Topologie und die Dualitaetssaetze , was written under the direction of Willem van der Woude .
Van Kampen received his Ph. D. degree from Leiden University in 1929 .
Van Kampen 's dissertation , entitled Die kombinatorische Topologie und die Dualitaetssaetze , was written under the direction of Willem van der Woude .
Van Kampen received his Ph. D. degree from Leiden University in 1929 .