Virkki, Niilo. “High Chromosome Number and Giant Postreductional Sex Chromosomes in the Beetle Walterianella Venusta Schaufuss (Chrysomelidae, Alticinae)”. The Journal of Agriculture of the University of Puerto Rico, vol. 47, no. 3, July 1963, pp. 154-63, doi:10.46429/jaupr.v47i3.12947.