Santos, J. N. A. D. J., Silveira, O. T. and Carpenter, J. M. (2017) “A new species of the genus Protopolybia Ducke, 1905 (Hymenoptera, Vespidae, Polistinae), with taxonomic contributions to the exigua species-group”, Zootaxa. Auckland, New Zealand, 4286(3), pp. 432–438. doi: 10.11646/zootaxa.4286.3.11.