29.3 29.4 29.5 29.6 "Lettuce". University of Illinois Extension. සම්ප්‍රවේශය 25 මාර්තු 2012.↑ Koopman, Wim J.M.; Guetta, Eli; van de Wiel, Clemens C.M.; Vosman, Ben; van den Berg, Ronald G (1998). "Phylogenetic relationships among Lactuca (Asteraceae) species and related genera based on ITS-1 DNA sequences". American Journal of Botany. 85 (11): 1517–1530. doi:10.2307/2446479. JSTOR 2446479. PMID 21680311.{{cite journal}}:  CS1 maint: multiple names: authors list (link)↑ Davey, et al., p. 241.↑ 32.0 32.1 32.2 Miles, Carol. "Winter Lettuce". Washington State University. සම්ප්‍රවේශය 26 මාර්තු 2012.↑ Katz and Weaver, p. 375.↑ Larkcom, Joy and Phillips, Roger (2003). The Organic Salad Garden. Frances Lincoln Ltd. p. 12. ISBN 0-7112-2204-5.{{cite book}}:  CS1 maint: multiple names: authors list (link)[permanent dead link]↑ 35.0 35.1 Hullin, R. P. (28 ජූනි 2007). "The lithium contents of some consumable items". International Journal of Food Science & Technology. 4 (3): 235–240. do