1. Representation of Cognitive Structures – Syntax and Semantics of French Sentential Complements;Achard,1998
2. On the -ra form;Bolinger;Hispania,1948
3. One subjunctive or two?;Bolinger;Hispania,1974
4. El subjuntivo: valores y usos;Borrego,1987
5. Gramática Descriptiva de la Lengua Española 2;Bosque Muños,1999