Kawai, L. A., Pinotti, M. H. P. and Celligoi, M. A. P. C. (2006) “Exopolysaccharide production by the cyanobacteria Nostoc sp in different concentrations of nitrogen and glucose”, Semina: Ciências Biológicas e da Saúde, 27(1), pp. 33–39. doi: 10.5433/1679-0367.2006v27n1p33.