Structure and functioning of plant populations 2, Phenotypic and genotypic variation in plant populations : [Second International Symposium on the Structure and Functioning of Plant Populations held on 7-11 May 1984 in Wageningen, organized by the Institute for Ecological Research and the University of Groningen] / editors, J. Haeck and J.W. Woldendorp ; Koninklijke Nederlandse akademie van wetenschappen / Amsterdam : North-Holland Publiishing Company , 1985