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. http://encore.lib.warwick.ac.uk/iii/encore/record/C__Rb3442466.
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. http://catdir.loc.gov/catdir/enhancements/fy0737/97145967-b.html.
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. Electronic resource. Oxford: Oxford University Press. http://0-www.oxfordreference.com.pugwash.lib.warwick.ac.uk/view/10.1093/acref/9780191739538.001.0001/acref-9780191739538.