Darwin, C., Barrett, P. H., & Freeman, R. B. (1989). The formation of vegetable mould through the action of worms with observations on their habits. Pickering.
Chicago-referens (17:e uppl.)Darwin, Charles, Paul H. Barrett, och R. B. Freeman. The Formation of Vegetable Mould Through the Action of Worms with Observations on Their Habits. London: Pickering, 1989.
MLA-referens (8:e uppl.)Darwin, Charles, et al. The Formation of Vegetable Mould Through the Action of Worms with Observations on Their Habits. Pickering, 1989.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.