APA

United States, . (19). Annual report of the Governor of Porto Rico. Washington: United States Government Printing Office.

Chicago

United States, . 19. Annual report of the Governor of Porto Rico. Washington: United States Government Printing Office.

Harvard

United States, . (19). Annual report of the Governor of Porto Rico. Washington: United States Government Printing Office.

MLA

United States, . Annual report of the Governor of Porto Rico. Washington: United States Government Printing Office. 19.