ISBN 0-478-01114-8* R. G. Powlesland, A. Roberts, B. D. Lloyd, D. Merton: "rsnz.org: Number, fate, and distribution of Kakapo ("Strigops habroptilus") found on Stewart Island, New Zealand 1979–1992.
ISBN 0-478-01114-8* R. G. Powlesland, A. Roberts, B. D. Lloyd, D. Merton: "Number, fate, and distribution of Kakapo (Strigops habroptilus) found on Stewart Island, New Zealand 1979—1992.