Olsen, L. (2013). Tracks and signs of the animals and birds of Britain and Europe. Princeton University Press.
Chicago Style (17. basım) AtıfOlsen, Lars-Henrik. Tracks and Signs of the Animals and Birds of Britain and Europe. Princeton University Press, 2013.
MLA (9th ed.) AtıfOlsen, Lars-Henrik. Tracks and Signs of the Animals and Birds of Britain and Europe. Princeton University Press, 2013.
Uyarı: Bu alıntı herzaman %100 doğru olmayabilir..