ニルス・ガブリエル・セフストレーム
“The Discovery of the Elements: VII. Columbium, Tantalum, and Vanadium”. Journal of Chemical Education 9 (5): 863–884. Bibcode: 1932JChEd...9..863W. doi:10.1021/ed009p863. http://search.jce.divched.org/JCEIndex/FMPro?-db=jceindex.fp5&-lay=wwwform&combo=vanadium&-find=&-format=detail.html&-skip=14&-max=1&-token.2=14&-token.3=10. - subscription required
Svenskt biografiskt handlexikon: Sefström, Nils Gabriel - in Swedish