APA
International Association O. c. o. p. I., . (1967). The police yearbook 1968. U.S.A: Impreso.
Chicago
International Association Of chiefs of police INC, . 1967. The police yearbook 1968. U.S.A: Impreso.
Harvard
International Association O. c. o. p. I., . (1967). The police yearbook 1968. U.S.A: Impreso.
MLA
International Association Of chiefs of police INC, . The police yearbook 1968. U.S.A: Impreso. 1967.