Literature
- Bieri, S. 2002. Die Bienen und Wespen des Fürstentums Liechtenstein. Amtlicher Lehrmittelverlag.
- Williams, P. H. 1998. An annotated checklist of bumble bees with an analysis of patterns of description (Hymenoptera: Apidae, Bombini) Bulletin of the Natural History Museum (Entomology), vol. 67, no. 1 pp 79-152.