APA (7e ed.) Bronvermelding

Brown Gfrorer, B. S. S. Listen, speak, read and understand. Universidad de Costa Rica.

Chicago (17e ed.) Bronvermelding

Brown Gfrorer, Bonnie; Smith Sharp. Listen, Speak, Read and Understand. San José, Costa Rica: Universidad de Costa Rica.

MLA (9e ed.) Bronvermelding

Brown Gfrorer, Bonnie; Smith Sharp. Listen, Speak, Read and Understand. Universidad de Costa Rica.