DR rate coefficients of S iv: red solid curve, present IC; blue solid curve, present LS; green solid curve, previous recommended compilation (Mazzotta et al. 1998); gray dashed curve, present RR rate coefficient; (a) black dashed curve, Burgess formula (Aldrovandi & Péquignot 1973); (b) black squares, LS (Jacobs et al. 1979); (c) black dash dotted curve, empirical formula (Mewe et al. 1980); (d) open circles, fitted data (Shull & Van Steenberg 1982); (f) magenta solid curve, LSR-matrix, RR + DR (Nahar & Pradhan 1995; Nahar 1996, 2000); (g) black solid curve, LS AUTOSTRUCTURE (Badnell 1991); and (h) open stars, LS (Al-Mulhem & Nasser 1992).