1. Allen, E. J., 1978. Plant density. In: The potato, the scientific basis for improvement. Chapter 7. Chapman & Hall, London.
2. Burton, W. G. 1966. The potato. Veenman. Wageningen.
3. Emilsson, B., 1949. Studies on the rest period and dormant period in the potato tuber.Acta. agric. scand. 3: 189–284.
4. Moorby, J. & F. L. Milthorpe, 1975. Potatoes. In: L. T. Evans (Ed.), Crop physiology, some case histories, Chapter 8, Cambridge University Press. Cambridge.
5. Wurr, D. C. E., 1975. Relationships between sprouting characters and stem development in two maincrop potato varieties.Potato Res. 18: 83–91.