Cita APA (7a ed.)
Penny, R. Variation and Change in Spanish. Cambridge University.
Cita estilo Chicago (17a ed.)
Penny, Ralph. Variation and Change in Spanish. Cambridge, Inglaterra: Cambridge University.
Cita MLA (9a ed.)
Penny, Ralph. Variation and Change in Spanish. Cambridge University.
Precaución: Estas citas no son 100% exactas.