Weiss, K., Strohm, E., Kaltenpoth, M., & Herzner, G. (2015). Comparative morphology of the postpharyngeal gland in the Philanthinae (Hymenoptera, Crabronidae) and the evolution of an antimicrobial brood protection mechanism. BMC Evolutionary Biology, 15: 291. doi:10.1186/s12862-015-0565-0.