Sarno, D., Kooistra, W.H.C.F., Balzano, S., Hargraves, P.E. & Zingone, A. (2007). Diversity in the genus Skeletonema (Bacillariophyceae): III. Phylogenetic position and morphological variability of Skeletonema costatum and Skeletonema grevillei, with the description of Skeletonema ardens sp. nov. Journal of Phycology, 43: 156-170