pp. 106-107. Hoppenrath, M., Elbrachter, M., Drebes, G. (2009) Marine Phytoplankton, Selected microphytoplankton species from the North Sea around Helgoland and Sylt. pp. 59, figure 5. Plate 24, page 58:fig. f-k. E. Schweizerbart’sche Verlagsbunchhandlung, Stuttgart, Germany.