Citing abstracts

Hello everyone! A lot of poster abstracts are available at wormbase, they are given as WBPaperXXX. Is it possible to cite these abstracts in PhD theses? Or do I have to ask the author for permission to cite the information as personal communication? Thanks in advance!

Anything reported in a meeting abstract or in the Worm Breeder’s Gazette is to be treated as a personal communication, and should be cited only as such and with the permission of the authors.