I just tried a full and a partial GEDCOM export, both included the sources. The GEDCOM is a plain text file and can be opened and viewed with a text editor like WordPad, Word or Word Perfect. (Just don't edit anything and save it unless you know what you are doing.) The soures are grouped at the end of the GEDCOM, each with a header such as: "0 @S1@ SOUR". I don't know where your problem is as I can't seem to replicate it.