Patil, Tejaswini, et al. “Influence of Irrigation Interval, Nitrogen Level and Crop Geometry on Production of Trickle Irrigated Lettuce”. Indian Journal of Horticulture, vol. 69, no. 03, Sept. 2012, pp. 360-8, https://journal.iahs.org.in/index.php/ijh/article/view/2004.