Please help me complete my set of vintage primes! :)

[christianhubbard]

Ok guys so here's the deal, I inherited a Vivitar set of primes (28mm f2.8, 50mm f1.8, and 125mm f2.8) from my mother. I'd love to have an 85mm to complete the set (excluding a 35???) but I can't seem to find one anywhere! :'(

I'm sure several of you guys are much more savvy than I, as I don't know where to look other than ebay. (keh camera?)

Anyway, any help you guys can give would be much appreciated.

pictures of one of the lenses: http://imgur.com/a/Pude9

[christianhubbard]

They are all m42 screw mount, if that helps at all?  :)