Thuja er ættkvísl barrtrjáa í Cupressaceae (Grátviðarætt). Það eru fimm viðurkenndar tegundir í ættkvíslinni, tvær ættaðar frá Norður-Ameríku og þrjár í austur Asíu.
↑ 1,01,11,2"Thuja". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
↑Farjon, A. (2005). Monograph of Cupressaceae and Sciadopitys. Kew: Royal Botanic Gardens. ISBN1-84246-068-4.
↑Earle, Christopher J., ed. (2018). "Thuja". The Gymnosperm Database.
↑ Chambers, Kenton L. (1993). "Thuja". In Flora of North America Editorial Committee. Flora of North America North of Mexico (FNA). 2. New York and Oxford – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
↑„GRIN Species Records of Thuja“. Germplasm Resources Information Network. United States Department of Agriculture. Afrit af upprunalegu geymt þann 24. september 2015. Sótt 22. janúar 2013.
↑"Thuja". County-level distribution maps from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014.