Template:Roskam, 2013
- Roskam, J.C. 2013: Biosystematics of insects living in female birch catkins. V. Chalcidoid ectoparasitoids of the genera Torymus Dalman, Aprostocetus Westwood, Psilonotus Walker and Eupelmus Dalman (Hymenoptera, Chalcidoidea). Tijdschrift voor entomologie 156(1): 21-34. DOI: 10.1163/22119434-00002020