Effect of beta-mercaptoethanol or epidermal growth factor supplementation on in vitro maturation of canine oocytes collected from dogs with different stages of the estrus cycle. 3 [% w @) n2 R, }3 N % i# h- A8 \/ G; M: a- t 9 I0 E* K$ _$ mhttp://www.ncbi.nlm.nih.gov/pubmed/15365241