Gillison, A.N., Liswanti, N. Budidarsono, S., van Noordwijk, M. and Tomich, T.P. (2004). Impact of cropping methods on biodiversity in coffee agroecosystems in Sumatra, Indonesia. Ecology and Society 9: 7. [online] URL: http://www.ecologyandsociety.org/vol9/iss2/art7
