P. Westbroek, E.W. de Vrind-de Jong, P. van der Wal, A.H. Borman, and J.P.M de Vrind. 1985. “Biopolymer-Mediated Ca and Mn Accumulation and Biomineralization ”. Netherlands Journal of Geosciences, January, 5-15. https://njgjournal.nl/index.php/njg/article/view/13159.