J. I. M.  Melo, ?Synopsis of Boraginaceae sensu lato in the Caatingas of the São Francisco River, Northeastern Brazil?, Anales del Jardín Botánico de Madrid, vol. 72, p. e013, 2015.

F.  Luebert and Hilger, H. H., ?Typification of Heliotropium and Tournefortia (Heliotropiaceae) species described by Ruiz and Pavón?, Anales del Jardín Botánico de Madrid, vol. 71, p. e012, 2014.