Aragonés, Luis, and Ramón Palencia. 2009. Gramática de Uso Del Español: Teoría y Práctica B1 B2: Con Solucionario. Madrid: Ediciones SM.
Butt, John, Carmen Benjamin, and Antonia Moreira Rodríguez. 2019. A New Reference Grammar of Modern Spanish. Sixth edition. London: Routledge, Taylor & Francis Group.
Love, Catherine E., and Gaëlle Amiot-Cadey. 2009. Collins Spanish Dictionary =: Collins Universal Español-Inglés, English-Spanish. 9th ed. Glasgow: Collins.
National Textbook Company. 1997. Repaso: A Complete Review Workbook for Grammar, Communication, and Culture. Lincolnwood, Ill., USA: National Textbook Co.
Pountain, Christopher J., Teresa de Carlos, and Angela Howkins. 2011. Practicing Spanish Grammar. 3rd ed. London: Hodder Education.
Rollin, Nicholas, Carvajal, Carol Styles, and Horwood, Jane. 2009. The Pocket Oxford Spanish Dictionary: Spanish-English. Oxford: Oxford University Press.