APA-viite (7. p.)

Howcroft, N., & Davidson, J. (1974). Papua New Guina tree introduction and improvement progress report 1972-1974. Dept. of Forests.

Chicago-viite (17. p.)

Howcroft, N., ja John Davidson. Papua New Guina Tree Introduction and Improvement Progress Report 1972-1974. Boroko: Dept. of Forests, 1974.

MLA-viite (9. p.)

Howcroft, N., ja John Davidson. Papua New Guina Tree Introduction and Improvement Progress Report 1972-1974. Dept. of Forests, 1974.