You will not find anything better than this article:

Hawksworth, D.L. and Sherwood, M.A. (1981) A reassessment of three widespread resinicolous Discomycetes. Canad. J. Bot. 59: 357-372.

It includes the key for Sarea (both anamorphs and teleomorphs).

Hi Rolands,

This is all I have for Sarea (apart from some more popular books with no key). Only two species are keyed, but as far as I remember I had some collection that didn't fit into either of these two. I have just few pages of Purvis (2000) Lichens as jpegs. I am sending you the page displaying the key.

Cheers,

Neven

I'm thankful for your answers :) All this information is useful for me..

Dear Rolands,

I've already sent  a paper dealing with this genus to a journal. There is a comprehensive morphological and anatomical study of S. resinae and S. difformis,  Unfortunately, it will be published in autumn. I will send a copy to you then.

Regards,

Isaac