Villegas, B. M. (1983). Strategies for crisis. Center for Research and Communication.
Chicago Style aipamenaVillegas, Bernardo M. Strategies for Crisis. [Pasig, Metro Manila]: Center for Research and Communication, 1983.
MLA aipamenaVillegas, Bernardo M. Strategies for Crisis. Center for Research and Communication, 1983.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.