Schulze, E. D., Oren, R., & Lange, O. L. (1989). Nutrient relations of trees in
healthy and declining Norway spruce stands. In E.-D. Schulze, O. L. Lange, & R. Oren (Eds.),
Forest Decline and Air Pollution, Ecological Studies (pp. 392-417). Berlin, Heidelberg:
Springer.
