1. Ayasse, M., Stökl, J., Francke, W. (2011) Chemical ecology and pollinator-driven speciation in sexually deceptive orchids. Phytochemistry, Plant-Insect Interact. 72, 1667–1677
2. Baker, H.G., Baker, I. (1990) The predictive value of nectar chemistry to the recognition of pollinator types. Isr. J. Bot. 39, 157–166
3. Behmer, S.T., Nes, W.D. (2003) Insect sterol nutrition and physiology: a global overview. Adv. Insect Physiol. 31, 1–72
4. Benton, T. (2006) Bumblebees: the natural history & identification of the species found in Britain. Collins, London
5. Beug, H.-J. (2004) Leitfaden der Pollenbestimmung für Mitteleuropa und angrenzende Gebiete. Friedrich Pfeil, München, Germany