Andrew C. Roberts, Mark A. Cooper, Frank Christopher Hawthorne, Alan J. Criddle, John A. R. Stirling: Sewardite, CaFe3+2(AsO4)2 (OH)2,a new mineral from Tsumeb, Namibia. In: The Canadian Mineralogist. Band40, 2002, S.1191–1198, doi:10.2113/gscanmin.40.4.1191 (rruff.info [PDF; 521kB]).
Andrew C. Roberts, Mark A. Cooper, Frank Christopher Hawthorne, Alan J. Criddle, John A. R. Stirling: Sewardite, CaFe3+2(AsO4)2 (OH)2,a new mineral from Tsumeb, Namibia. In: The Canadian Mineralogist. Band40, 2002, S.1191–1198, doi:10.2113/gscanmin.40.4.1191 (rruff.info [PDF; 521kB]).