Trevor Clarke, Joseph Grows Cocoa, revised by Colin Benton & Jane Belfield (CQIP, Rabaul), drawings by Blasius Offele, Mar 1993
John Perkins and Trevor Clarke, An Alternative Policy for Cocoa in Papua New Guinea: a discussion paper, Rabaul, Aug 1980
John Perkins and Trevor Clarke, Narapela pasin long ronim bisnis kakau insait long Papua Niugini, Rabaul, Aug 1980 with An Alternative Cocoa Policy for Papua New Guinea
P. Bleeker and D.F. Freyne, A Preliminary Inventory of Areas Suitable for Cocoa Production in Papua New Guinea, 1981
J.E. Moxon, Review of Research requirements for Cocoa in Papua New Guinea: Report to the Government and Cocoa Board of PNG, compiled by the Cocoa Research Group of PNG, LAES, Keravat, July 1983
Arthur Stevenson, ‘Cocoa Outlook’, Futures Focus, Vol.2, No.3, 13 Mar 1989.
James Guest, The Cocoa, Coffee and Copra Price Stabilisation Schemes in Papua New Guinea’s Post-Independence Macroeconomic Policy Framework, ACIAR Working Paper No.28, 1989
Harvest, Vol.9, Nos.3-4, 1983, special issue on Cocoa production
