http://www.cyber-adviseurs.nl/uploads /file/Het%20geslacht%20Tetradium,%20de%20Bijenboom.pdf
Het geslacht Tetradium, de Bijenboom
https://www.youtube.com/watch?v=McwvmJDT2-0
De Bijenboom, videofragment
http://www.bieenkorf.be/plantengids.htm
Plantengids
http://resistantbees.com/index_n.html
Onderzoek naar bijenleven
http://www.pollinator.org/poster2016
Pollinator Partnership
http://ebcd.org/wp-content/uploads/2016/05/Food-security-and-nutrition-Dr.-Lucas-Garibaldi-Universidad-Nacional-de-Rio-Negro-Part-1.pdf
http://ebcd.org/wp-content/uploads/2016/05/Food-security-and-nutrition-Dr.-Lucas-Garibaldi-Universidad-Nacional-de-Rio-Negro-Part-2.pdf
European parliament, bee-week, info