Nelson, Rebekah A., and Terry L Griswold. “The Floral Hosts and Distribution of a Supposed Creosote Bush Specialist, Colletes Stepheni Timberlake (Hymenoptera: Colletidae)”. Journal of Melittology, no. 49, May 2015, pp. 1-12, https://doi.org/10.17161/jom.v0i49.4836.