Cleverdon, C.W. (1960). "The Aslib Cranfield Research Project on the Comparative Efficiency of Indexing Systems". ASLIB Proceedings. 12 (12). Emerald: 421–431. doi:10.1108/eb049778. ISSN0001-253X.
Cleverdon, Cyril (1967). "The Cranfield Tests on Index Language Devices". ASLIB Proceedings. 19 (6). Emerald: 173–194. doi:10.1108/eb050097. ISSN0001-253X.
Cleverdon, C.W. (1960). "The Aslib Cranfield Research Project on the Comparative Efficiency of Indexing Systems". ASLIB Proceedings. 12 (12). Emerald: 421–431. doi:10.1108/eb049778. ISSN0001-253X.
Cleverdon, Cyril (1967). "The Cranfield Tests on Index Language Devices". ASLIB Proceedings. 19 (6). Emerald: 173–194. doi:10.1108/eb050097. ISSN0001-253X.