Stefano, M., A. Papini, and L. Brighigna. “A New Quantitative Classification of Ecological Types in the Bromeliad Genus Tillandsia (Bromeliaceae) Based on Trichomes”. Revista De Biología Tropical, vol. 56, no. 1, Mar. 2008, pp. 191–203, doi:10.15517/rbt.v56i1.5518.