Historians and the Use of Primary Source Materials in the Digital Age, Alexandra Chassanoff, 2013/9/1.  American Archivist. Volume 76 Issue 2 Pages 458-480.Society of American Archivists

“This study examines how academic historians search for, access, and use primary source  materials in their research pursuits. Recruited historians completed an online questionnaire about current information practices and potential information needs in archival settings. The  results shed light on the most frequent methods historians use to search for primary source materials; the types of primary source documents they are most likely to use; whether they  access materials online or in person; their use of digitized archival collections; factors they consider important in their discussion to use archival collections; and what might prevent them from using these collections.”