| Auteur(s) | Else, G.R. & Edwards, M. |
| Jaar | 2018 |
| Titel | Handbook of the Bees of the British Isles. Ray Society, LondonFalk, S. 1991. A review of the scarce and threatened bees, wasps and ants of Great Britain. Research and Survey in Nature Conservation 35: 1-344. |