K. B. Esho, K. A. Omer, S. M. Tuma, and S. S. Hussein, “EFFECT OF SOAKING SEEDS IN ZINC SULPHATE SOLUTION ON VEGETATIVE GROWTH , FLOWERING AND YIELD , OF TWO CULTIVARS OF PEA (Pisum sativum L. ) . ”, DASJ, vol. 1, no. 2, pp. 66–77, Dec. 2009.