Butler, R. W. (1991). Preservation of Library Materials. Agri-Topics No. AT 92-01.
Citazione stile Chigago Style (17a edizione)Butler, Robert W. Preservation of Library Materials. Agri-Topics No. AT 92-01. 1991.
Citatione MLA (9a ed.)Butler, Robert W. Preservation of Library Materials. Agri-Topics No. AT 92-01. 1991.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.