REFERENCES
- Atanassov At. (1988) Biotechnologia v rastenievodstvoto, Zemizdat, Sofia, 122,216.
- Gantchev P., Garelkova Z., Gyuleva V. (1989) Biotechnology and bioindustry, 6, 23–26.
- Ivanov A.F. (1970) Rost drevesnih rastenii i kislotnost pochvi, p.37.
- Kalinin F., Sarnachkaya V. et al.. (1980) In vitro methods in the plant's physiology, p.371.
- Gradinarski L. (1984) In: Proceeding of the Second International Symposium on Plant Nutrition, vol. 4, Sofia, 395–398, 399–402.