Rito, C. 2009. On surfaces with p_g = q = 1 and non-ruled bicanonical involution. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE. 6, 1 (Dec. 2009), 81-102. DOI:https://doi.org/10.2422/2036-2145.2007.1.05.