APA

Puerto Rico, . (1977). Annual report. San Juan, P.R: Publishing Resources, Inc.

Chicago

Puerto Rico, . 1977. Annual report. San Juan, P.R: Publishing Resources, Inc.

Harvard

Puerto Rico, . (1977). Annual report. San Juan, P.R: Publishing Resources, Inc.

MLA

Puerto Rico, . Annual report. San Juan, P.R: Publishing Resources, Inc. 1977.