Homosexual behaviour in animals :  an evolutionary perspective / 
editors by Volker Sommer, Paul L. Vasey 
 - New York :  Cambridge University Press ,  c2006 
 - ix, 382 p. :  ill. ;  26 cm. 
<br/><br/>Includes bibliographical references and index 
<br/><br/><label>ISBN: </label>9780521182300 (pbk.) 9780521864466 (hbk.) 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Homosexuality in animals<br/>Sexual behavior in animals