Rodríguez Ramón, Andrés. Permanencia de Rubén Darío. - Charlotte, N.C. Heritage Printers 1967. - x, 295 p. 21 cm. Includes bibliographical references. LCCN: 68001251 Subjects--Personal Names: Darío, Rubén, 1867-1916. LC Class. No.: PQ7519.D3 / Z8737 Dewey Class. No.: 868