Escamilla MA, Batki S, Reus VI, Spesny M, Molina J, Service S, Vinogradov S, Neylan T, Mathews C, Meza L, Gallegos A, Montero AP, Cruz ML, Neuhaus J, Roche E, Smith L, Leon P, Freimer NB. Comorbidity of bipolar disorder and substance abuse in Costa Rica: pedigree- and population-based studies. J Affect Disord. 2002 Sep;71(1-3):71–83. doi: 10.1016/s0165-0327(01)00373-1. PMID: 12167503.