http://www.ots.ac.cr/tropiweb/attachments/volumes/vol56-4/Akinsanya-Gas…
http://www.izs.it/vet_italiana/2010/46_1/21.pdf
http://www.sciencepub.net/life/life0702/07_3342life0702_35_41.pdf
http://www.ajol.info/index.php/jasem/article/viewFile/65683/53373
http://www.ajol.info/index.php/tzool/article/view/73130