Gonzalez, V. H., P. A. Sepúlveda, and T. L. Griswold. “Taxonomic Notes on American Heriades Spinola, 1808 and Leioproctus Smith, 1853 (Hymenoptera: Megachilidae, Colletidae)”. Zootaxa, vol. 3591, no. 1, Dec. 2012, pp. 75–78, doi:10.11646/zootaxa.3591.1.4.