Citing a personal communication is much better than citing nothing at all. I have used an email from a representative of Babson College, for example, on the Babson College Talk page, as a reference for whether or not their giant world globe rotates. (It was built to rotated and once rotated but it doesn't now). But these aren't _good_ references and do _not_ meet Wikipedia's guidelines, which I believe are longstanding. The reason why publication is important is that by definition a published source is widely available and easily checked. As I have personally found, it is not always easy to "call the guy and ask the same question." Among other things, you may not have his contact information. (It would be a serious breach of etiquette and privacy to include that in the reference). And you are basically requiring every reader who wants to verify the information to establish a personal contact with the source. That's just not reasonable. Finally, the requirement of publication puts a very rough-and-ready filter in place. In order to publish something, the author _usually_ has to convince at least _one_ other person that it is worth publishing... and spending money on. That's not an absolute test of truth, but it is at least a filter. Over the phone, someone can say anything to me that they like. Thus, a personal communication is a poor reference for the same reason that a personal website is a poor reference: anyone can say anything they like, without even the slightest necessity of passing any kind of vetting process. Actually, a phone call is worse: a personal website is, at least, out in the open and subject to inspection.