APA (7e ed.) Bronvermelding

Hartwig, G. (1881). The polar world: A popular description of man and nature in the Arctic and Antarctic regions of the globe (Segunda edición.). Longmans, Green, and Co.

Chicago (17e ed.) Bronvermelding

Hartwig, G. The Polar World: A Popular Description of Man and Nature in the Arctic and Antarctic Regions of the Globe. Segunda edición. London, England, United Kingdom: Longmans, Green, and Co, 1881.

MLA (9e ed.) Bronvermelding

Hartwig, G. The Polar World: A Popular Description of Man and Nature in the Arctic and Antarctic Regions of the Globe. Segunda edición. Longmans, Green, and Co, 1881.