Beg, A. R., Ahmad, M., (1974). Pakistan Journal of Forestry 24(1), 69-76. English language
Burdekin, D. A., (1979). Arboricultural Leaflet, Department of the Environment(No. 5), 41 pp. English language
Marinkovic, P., (1953). Sumarstvo 6(5), 443-56. Serbo-Croatian language
Jones, E. W. , (1945). Journal of Ecology 32(2), 215-252 pp. English language