1. Hasanzade A. The effect of different amounts of nitrogen fertilizer on yield and yield component and grain oil of sunflower. Uremia Agri. Sci. Res. 2002;2:25-33. (In Persian)
2. Zargari A. Medicinal herbs. Vol. 1, University of Tehran Press, Tehran, 1987. (In Persian)
3. Omidbeigi R. Approaches to production and processing of medicinal herbs. Vol. 1, Fekre Now Publication, Tehran, 1995. (In Persian)
4. Najafpoor M. Subjects about medicinal plant of fenugreek (Trigonella foenum gracum L.). Research Forest and Range Institute, Iran, 1994. (In Persian)
5. Gardner FP, Pearce RB, Mitchell RL. Physiology of crop plants. Iowa State Press, 1984.
6. Koocheki A, Nassiri Mahallati M, Azizi G. Effect of different irrigation intervals and plant densities on yield and yield components of two fennel (Foenicolum vulgare) landraces. Iranian J Agric Res. 2006;4:131-140. (In Persian)
7. Shokhmgar M. Effect of irrigation interval and N fertilization on qualitative and quantitative characteristics of fenugreek. M.Sc. Thesis, Islamic Azad University, Birjand Branch, Birjand, Iran, 2009. (In Persian)
8. Lebaschi MH, Sharifieashorabadi A. Growth indices of some medicinal plants in different drought stress conditions. Iranian J Med Arom Plants 2004;20:249-261. (In Persian)
9. Khan MMA. Nitrogen application ameliorates the productivity of Nigella sativa L. In: Glimpses in Plant Research Vol. XI. Medicinal Plant: New Vistas of Research. 1993.
10. Ghanbari AK, Taheri Mazandarani M. Effects of sowing date and plant density on yield of pinto bean. Seed Plant J. 2003;19:483-496. (In Persian)
11. Sharma SK. Response of nitrogen and spacing on fenugreek seed production. Hortic J. 2000;13:39-42.
12. Gowda MC, Halesh DP, Farooqi AA. Effect of dates of sowing and spacing on growth of fenugreek (Trigonella foenum gracum L.). Biomedicine 2006;1:141-146.
13. Seghatoleslami MJ, Ahmadi Bonakdar K. The effect of sowing date and plant density on yield and yield components of fenugreek (Trigonella foenum gracum L.). Iranian J Med Arom Plants 2010;26:265-274. (In Persian)
14. Safikhani F, Heydarye Sharifabad H, Syadat A, Sharifi Ashorabadi A, Syednedjad M, Abbaszadeh B. The effect of drought on yield and morphologic characteristics of Deracocephalum moldavica L. Iranian J Med Arom Plants 2007;23:183-194. (In Persian)
15. Malik VS, Swanton CJ, Michaels TE. Interaction of white bean (Phaseolus vulgaris L.) cultivars, row spacing and seeding density with annual weeds. Weed Sci. 1993;41:62-68.
16. Modi H. Effect of plant density and N on yield and yield components of Nigella sativa. M.Sc. Thesis on Agriculture, Department of Agriculture, Ferdowsi University of Mashad, Mashad, Iran, 1999. (In Persian)
17. Husain MW, Hill GD, Gallagher JN.The response of field beans (Vicia faba) to irrigation and sowing date. J Agric Sci Camb. 1988;111:233-254.
18. Holshouser DL, Whittaker JP. Plant population and row spacing effects on early soybean production systems in the mid-Atlantic USA Agron J. 2002; 94:603-611.
19. Singh V, Sharma SK, Verma BL, Singh V. Response of rainy season sunflower (Helianthus annuus) to irrigation and nitrogen under north western Rajasthan. Indian J Agron. 1995;40:239-242.
20. Taylor AJ, Smith CJ, Wilson IB. Effect of irrigation and nitrogen fertilizer on yield, oil content, nitrogen accumulation and water use of canola (Brassica napus L.). Fertil Res. 1991;29:249-260.
21. Rosalind AB, Purcel LC, Vories ED. Short season soybean yield compensation in response to population and water regime. Crop Sci. 2000;40:1070-1078.
22. Shirtliffe SJ, Johnston AM. Yield density relationships and optimum plant populations in two cultivars of solid-seeding dry bean grown in Saskatchewan. Can J Plant Sci. 2002;82:521-529.
23. Singh S, Buttar GS, Singh SP, Brar DS. Effect of different dates of sowing and row spacing on yield of fenugreek (Trigonella foenum gracum). J Med Arom Plant Sci. 2005;27:629-630.
24. Yadav JS, Jagdev S, Virender K, Yadav BD. Effect of sowing time, spacing and seed rate on seed yield of fenugreek (Trigonella foenumgracum L.) on light textured soil. Haryana Agric Uni J Res. 2000;30:107-111.
25. Seghatoleslami MJ, Mousavi SGR. Effect of sowing date and plant density on grain and flower yield of pot marigold (Calendula officinalis L.). Iranian J Agric Res. 2008;6:263-269.
26. Martin RJ, Deo B. Effect of plant population on Calendula officinalis flower production. New Zealand J Crop Hortic Sci. 2000;28:37-44.