To find primary documents from/about Latin America and the Caribbean at Duke University's David M. Rubenstein Rare Book & Manuscript Library, search the Duke University Libraries catalog limiting your ADVANCED SEARCH by Location to Rubenstein Library. Search for SUBJECTS such as country name, personal name or research theme.
The Seminar on the Acquisition of Latin American Library Materials (SALALM) keeps a very useful online list of primary source digital projects located at member libraries.
Online Resources