1. Acikgoz, F. E. and S. Altintas. 2011. Seasonal variations in vitamin C and mineral contents and some yield and quality parameters in komatsuna (Brassica rapa var. pervidis). J. Food Agric. Environ. 9: 289–291.
2. Biesiada, A. 2008. Effect of flat covers and plant density on yielding and quality of kohlrabi. J. Elementol. 13: 167–173.
3. Buta, E. and A. S. Apahidean. 2009. Observations concerning the effect of agryl on environmental factors of cabbage cultivated in plastic tunnel and field. Bull. UASVM Hort. 66: 404–408.
4. Cara, F., D. A. Moreno, G. Villora, A. El Gharbaoui, J. M. Ruiz and L. Romero. 2002. Metabolic activity of Chinese cabbage as influenced by growth conditions under direct covers. Proc. IX Simposio Iberico sobre Nutrición Mineral de las Plantas: 79–82.
5. Gimenez, C., R. F. Otto and N. Castilla. 2002. Productivity of leaf and root vegetable crops under direct cover. Sci. Hortic. 94: 1–11.