i:10.1111/j.1365-2621.1969.tb01519.x. ISSN 0950-5423. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)↑ 36.0 36.1 Bradley, pp. 129–132.↑ "Developing Multi-Species Insect Resistance in Romaine Lettuce". United States Department of Agriculture. සම්ප්‍රවේශය 5 අප්‍රේල් 2012.↑ "Lettuce: Integrated Weed Management". UC Pest Management Guidelines. University of California. අගෝස්තු 2007. සම්ප්‍රවේශය 3 අප්‍රේල් 2012.↑ "Production of Lettuce & Chicory by countries". UN Food & Agriculture Organization. 2011. සම්ප්‍රවේශය 28 අගෝස්තු 2013.↑ Koike, Steven T; Gladders, Peter; Paulus, Albert O. (2006). Vegetable Diseases: A Color Handbook. Gulf Professional Publishing. p. 296. ISBN 0-12-373675-7.{{cite book}}:  CS1 maint: multiple names: authors list (link)↑ "FAO Statistics Database". Food and Agriculture Organization of the United Nations. සම්ප්‍රවේශය 24 මාර්තු 2012.↑ 42.0 42.1 42.2 Katz and Weaver, p. 378.↑ 43.0 43.1 Simoons, Frederick J. (1991). Foo