Although E-mail/Blog/Wikis become popular media of communication among the science researchers, CSE (7th edition) does not recommend personal communications as “formal end references”. However, references to personal communications can be placed within the running text. In a separate “Notes” section, additional details about the communication can be provided.
Example: “……and most of these meningiomas proved to be inoperable (2003 letter from RS Grant to me; unreferenced. See “Notes”) while a few were not.”