Luebert, F., and J.  Wen. 2008. ?Phylogenetic analysis and evolutionary diversification of Heliotropium sect. Cochranea (Heliotropiaceae) in the Atacama Desert?. Systematic Botany 33(2):390 - 402. Retrieved  (http://www.bioone.org/doi/abs/10.1600/036364408784571635).