U.S. Bureau of the Census. (1951). Census of manufactures, 1949, Purto Rico. s.n.
Lua i Stíl Chicago (17ú heag.)U.S. Bureau of the Census. Census of Manufactures, 1949, Purto Rico. Washington: s.n, 1951.
Lua MLA (9ú heag.)U.S. Bureau of the Census. Census of Manufactures, 1949, Purto Rico. s.n, 1951.
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