Question: Patricia Burford Ryan, an American writer of romance novels,  is the twin sister of the romance writer Pamela Burford whose books are currently available as what type of books?
Sentence (from "Tagalog pocketbooks"): Authors such as Maria Teresa Cruz San Diego, who used the pen names Maia Jose and Tisha Nicole, ventured into the fantasy romance genre, and into topics that are related to politics, ecology, gender issues, prostitution, mail-order bride syndicates, white slavery, non-governmental organizations, and breastfeeding programs.
Relevant evidence: No