@incollection{1019784, author = "Karl Hans Wedepohl", booktitle = "Sections B, C, E, I-M, O of Chapter 41 in: Wedepohl, K.H. (ex. ed.) Handbook of Geochemistry. Vol. II", publisher = "Springer: Berlin, Heidelberg, New York (1978)", title = "{N}iobium", year = "1978", }