BioStor
 | Bees in the collection of the California Academy of Science T D.a. Cockerell (1925) Proceedings of the California Academy of Sciences 14: 185-215 |
 | The type species of the genera and subgenera of bees Grace A Sandhouse (1943) Proceedings of the United States National Museum 92(3156): 519-619 |
 | FURTHER STUDIES ON THE WASPS OF JACKSON-HOLE WYOMING USA HYMENOPTERA ACULEATA H E Evans (1973) Great Basin Naturalist 33: 147-155 |
 | Genus-group names of bees and supplemental family-group names Charles D Michener (1997) Scientific Papers Natural History Museum University of Kansas 1: 1-81 |
 | The biology of Hoplitis (Robertsonella) simplex (Cresson), with a synopsis of the subgenus Robertsonella Titus John L Nuff (2009) Journal of Hymenoptera Research 18(2): 151-166 |