Cita APA (7a ed.)

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

Cita Chicago Style (17a ed.)

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

Cita MLA (9a ed.)

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