EDDY, N.O., et al. “Seasonal Variability of Phytoplankton Accessory Pigments (Chlorophyll-B and Chlorophyll-C) in the Calabar River Estuary: South Eastern Nigeria”. Asian Journal of Chemistry, vol. 19, no. 4, Mar. 2010, pp. 2711-20, https://asianpubs.org/index.php/ajchem/article/view/13368.