1. Beirnaert A. & R.Vanderweyen, 1940. Note préliminaire concernant l'influence du dispositif de plantation sur les rendements. Publs. Natn. Étude Agron. Congo Belge. Sér. Tech. 27: 26 pp.
2. Blaak G., L. D.Sparnaaij & T.Menendez, 1963. Breeding and inheritance of the oil palm. Part II. Methods of bunch quality. J. W. Afr. Inst. Oil Palm Res. 4: 145–155.
3. Breure C. J., 1977. Preliminary results from an oil palm density x fertiliser trial on young volcanic soils in West New Britain. In: D. A.Earp & W.Newall (Eds), International developments in oil palm. Kuala Lumpur, Incorporated Society of Planters. p. 192–207.
4. Breure C. J., 1982. Factors affecting yield and growth of oil palm tenera in West New Britain. Oléagineux 37: 213–228.
5. Breure C. J. & R. H. V.Corley, 1983. Selection of oil palms for high density planting. Euphytica 32: 177–186.