[[1] ASHRAFI, N.-V´AMOS, P.: On unit sum number of some rings, Q. J. Math. 56 (2005), 1-12.10.1093/qmath/hah023]Search in Google Scholar
[[2] JARDEN,M.-NARKIEWICZ,W.:On sum of units,Monatsh. Math. 150 (2007), 327-332.10.1007/s00605-006-0402-z]Search in Google Scholar
[[3] TICHY, R. F.-ZIEGLER, V.: Units generating the ring of integer of complex cubic fields, Colloq. Math. 109 (2007), 71-83.10.4064/cm109-1-6]Search in Google Scholar
[[4] ZELINSKY, D.: Every linear transformation is a sum of nonsingular ones, Proc. Am.Math. Soc. 5 (1954), 627-630.10.1090/S0002-9939-1954-0062728-7]Search in Google Scholar