APA

Dun and Bradstreet i., .International market guide: Puerto Rico. v. 1. New York: s.n.

Chicago

Dun and Bradstreet inc, .International market guide: Puerto Rico. v. 1. New York: s.n.

Harvard

Dun and Bradstreet i., .International market guide: Puerto Rico. v. 1. New York: s.n.

MLA

Dun and Bradstreet inc, .New York: s.n. .