APA

Rivera G., . (1931). A tentative bibliography of the Belles-Lettres of Porto Rico. Cambridge, Mass: Harvard University Press.

Chicago

Rivera Guillermo, . 1931. A tentative bibliography of the Belles-Lettres of Porto Rico. Cambridge, Mass: Harvard University Press.

Harvard

Rivera G., . (1931). A tentative bibliography of the Belles-Lettres of Porto Rico. Cambridge, Mass: Harvard University Press.

MLA

Rivera Guillermo, . A tentative bibliography of the Belles-Lettres of Porto Rico. Cambridge, Mass: Harvard University Press. 1931.