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-viite (17. p.)Darwin, Charles, Paul H. Barrett, ja R. B. Freeman. The Formation of Vegetable Mould Through the Action of Worms with Observations on Their Habits. London: Pickering, 1989.
MLA-viite (8. p.)Darwin, Charles, et al. The Formation of Vegetable Mould Through the Action of Worms with Observations on Their Habits. Pickering, 1989.
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