Shand, R. T., & Straatmans, W. (1974). Transition from subsistence: Cash crop development in Papua New Guinea. New Guinea Research Unit, The Australian National University.

Shand, R. T., and W. Straatmans. Transition from Subsistence: Cash Crop Development in Papua New Guinea. Port Moresby, New Guinea: New Guinea Research Unit, The Australian National University, 1974.

Shand, R. T., and W. Straatmans. Transition from Subsistence: Cash Crop Development in Papua New Guinea. New Guinea Research Unit, The Australian National University, 1974.