APA

Erdmann G. G., . (1979). Macronutrient deficienty symptoms in seedlings of four northem hardwoods. St. Paul: U. S. Department of Agriculture.

Chicago

Erdmann Gayne G, . 1979. Macronutrient deficienty symptoms in seedlings of four northem hardwoods. St. Paul: U. S. Department of Agriculture.

Harvard

Erdmann G. G., . (1979). Macronutrient deficienty symptoms in seedlings of four northem hardwoods. St. Paul: U. S. Department of Agriculture.

MLA

Erdmann Gayne G, . Macronutrient deficienty symptoms in seedlings of four northem hardwoods. St. Paul: U. S. Department of Agriculture. 1979.