I'm not sure, from reading the brief descriptions of the works of fiction under discussion, whether they're all about the development of a romantic relationship and a happy ending. Some of them seem to be more like snap-shots of relationships, however, the author of the article says this the analysis involves "emphasizing their continuity with the romance genre" so I'm including it.
Also commenting on Califia's writing, but with less about romance so not included elsewhere in the bibliography, is
Griffin, Gabriele. 1995. "Safe and Sexy? Lesbian Erotica in the Age of AIDS." Romance Revisited, eds. Lynne Pearce and Jackie Stacey. 143-157.