@inbook{87da69c9ee6c43e0902b65eb424fb40e,
title = "Physical resources of the humid tropics and theit relation to yield potentials of food crops",
author = "{van Keulen}, H.",
year = "1985",
language = "English",
pages = "31--59",
booktitle = "Potassium in the agricultural systems of the humid tropics : proceedings of the 19th colloquium of the International Potash Institute held in Bangkok/Thailand 1985",
publisher = "International Potash Institute",
note = "19th colloquium of the International Potash Institute ; Conference date: 25-11-1985 Through 29-11-1985",
}