When citing a personal corespondence, is the full name always mentioned? If you're citing a personal correspondence, e.g.:

"Cats are vicious" (Bill Bobson, personal correspondence, March 12, 2012) 

and you continue to use this personal correspondence with a cat expert, do you refer to them simply as Bobson, or Bill Bobson?
Continuously referring to personal correspondence sounds like a bad idea… if many parts of the discussion come from unpublished comments from your correspondent, he should probably be a co-author rather than simply cited. Otherwise, you can quote the personal correspondence once and explain its context at first point of use. Something like:


  Many of ideas developed in this paragraph were inspired by a series of discussion with cat expert Bill Bobson, over the spring of 2002. In particular, he drew our attention to the viciousness of cats and their unwillingness to comply to their master's will.