Erler, S.; Lattorff, H. M. G. (2010). "The degree of parasitism of the bumblebee (Bombus terrestris) by cuckoo bumblebees (Bombus (Psithyrus) vestalis)". Insectes Sociaux. 57 (4): 371-377. doi:10.1007/s00040-010-0093-2. ISSN0020-1812. S2CID853556.
Erler, S.; Lattorff, H. M. G. (2010). "The degree of parasitism of the bumblebee (Bombus terrestris) by cuckoo bumblebees (Bombus (Psithyrus) vestalis)". Insectes Sociaux. 57 (4): 371-377. doi:10.1007/s00040-010-0093-2. ISSN0020-1812. S2CID853556.
Erler, S.; Lattorff, H. M. G. (2010). "The degree of parasitism of the bumblebee (Bombus terrestris) by cuckoo bumblebees (Bombus (Psithyrus) vestalis)". Insectes Sociaux. 57 (4): 371-377. doi:10.1007/s00040-010-0093-2. ISSN0020-1812. S2CID853556.