Butlin, R. A., & Roberts, N. (1995). Ecological relations in historical times: Human impact and adaptation. Blackwell.
Chicago-viite (17. p.)Butlin, R. A., ja Neil Roberts. Ecological Relations in Historical Times: Human Impact and Adaptation. Oxford: Blackwell, 1995.
MLA-viite (9. p.)Butlin, R. A., ja Neil Roberts. Ecological Relations in Historical Times: Human Impact and Adaptation. Blackwell, 1995.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.