Bequaert, J. C. 1., Lang, H., & Chapin, J. P. (1918). A revision of the Vespidæ of the Belgian Congo: Based on the collection of the American Museum Congo expedition, with a list of Ethiopian diplopterous wasps. New York.

Bequaert, Joseph C. 1886-1982., Herbert Lang, and James Paul Chapin. A Revision of the Vespidæ of the Belgian Congo: Based On the Collection of the American Museum Congo Expedition, With a List of Ethiopian Diplopterous Wasps. New York, 1918.

Bequaert, Joseph C. 1886-1982., Herbert Lang, and James Paul Chapin. A Revision of the Vespidæ of the Belgian Congo: Based On the Collection of the American Museum Congo Expedition, With a List of Ethiopian Diplopterous Wasps. New York, 1918.