Wilmsen, Sakkia, Adrian G Dyer, and Klaus Lunau. “Conical Flower Cells Reduce Surface Gloss and Improve Colour Signal Integrity for Free-Flying Bumblebees”. Journal of Pollination Ecology 28 (July 9, 2021): 108–126. Accessed September 18, 2021. https://pollinationecology.org/index.php/jpe/article/view/606.