1. Aichner M, Stimpfl E (2002) Seasonal pattern and interpretation of mineral nutrient concentrations in apple leaves. Acta Hortic 594:377–382
2. Aktaş M, Ateş M (1998) Bitkilerde Beslenme Bozuklukları, Nedenleri ve Tanınmaları. Engin Yayınevi, Ankara, p 247
3. Anonymous (2006) Fertilizing apples. Spectrum Analytic, Washington, pp 1–23
4. Bergmann W (1992) Nutritional disorders of plants, development, visual and analytical diagnosis. Gustav Fischer, Jena, Stuttgart, New York, p 741
5. Drahorad W (1999) Modern guidelines on fruit tree nutrition. 42. Annual IDFTA Conference, Hamilton Ontario, Canada