Relative line strengths for the 3 s –3 p and 3 p –3 d transitions in O II and Ne II and the 4 s –4 p transitions in S II and A II have been calculated by quantum mechanics, using the intermediate coupling approximation. Landé g -values have been calculated and compared with experimental values. The parameters in the calculations have been determined empirically from observational spectroscopic data. Absolute strengths have been calculated by the Coulomb approximation. The strengths of the arrays 3 p – ns are discussed. Applications are made to the curve of growth of γ Pegasi.