The ratio $F^n_2$ / $F^p_2$ and the A dependence of nuclear ratios measured by NMC

Results are presented on the structure function ratio $F^n_2$ / $F^p_2$ and the A dependence of nuclear ratios $F^A_2$ / $F^C_2$ in deep inelastic muon scattering. Results were obtained for the hydrogen and deuterium targets with several incident energies, and for the nuclear targets at 200 GeV incident muon energy. Presented is an extension in x of the measured range of $F^n_2$ / $F^p_2$ down to a value of x=0.0008. Results are also shown for the nuclear ratios $F^A_2$ / $F^C_2$ , which cover the range 0.01 x 1 and 2 $Q^2$ 60 $GeV^2$. The extracted A dependence shows logarithmic behaviour at small and intermediate x.