Literature
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- Bieri, S. 2002. Die Bienen und Wespen des Fürstentums Liechtenstein. Amtlicher Lehrmittelverlag.
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- Söderman, G. and Leinonen, R. 2003. Suomen Mesipistiäiset ja niiden uhanalaisuus. Tremex Press Oy, Helsinki.
- Tomozei, B. 2008. Checklist of Bees of the genera Colletes Latreille 1930 and Hylaeus Fabricius 1793 of Romania (Hymenoptera: Apiformes: Colletidae) Faunistic Entomology – Entomologie faunistique 2008 61 (3), 87-97.