Compendium of Essential Reading for Trilingual Interpreters
http://www.interpretereducation.org/specialization/aslspanishenglish/ then click the ASL/Spanish/English Resources tab. On that page you will also find Toward Effective Practice: Interpreting in Spanish-Influenced Settings and Hacia Las Prácticas Efectivas: Interpretación en Situaciones Influenciadas por el Español