Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood (2016) The eBird/Clements checklist of birds of the world: Version 2016 http://www.birds.cornell.edu/clementschecklist/download, läst 2016-08-11
Avery, MI; Krebs, JR; Houston, AI (1988). "Economics of courtship-feeding in the European bee-eater (Merops apiaster)". Behavioral Ecology and Sociobiology. 23 (2): 61–67. doi:10.1007/BF00299888. S2CID13553144.
Roulston, TH; Goodell, K (2011). "The role of resources and risks in regulating wild bee populations". Annual Review of Entomology. 56: 293–312. doi:10.1146/annurev-ento-120709-144802. PMID20822447.
Roulston, TH; Goodell, K (2011). "The role of resources and risks in regulating wild bee populations". Annual Review of Entomology. 56: 293–312. doi:10.1146/annurev-ento-120709-144802. PMID20822447.
Avery, MI; Krebs, JR; Houston, AI (1988). "Economics of courtship-feeding in the European bee-eater (Merops apiaster)". Behavioral Ecology and Sociobiology. 23 (2): 61–67. doi:10.1007/BF00299888. S2CID13553144.