EN
Electron-positron (e-p) momentum densities in Mg are studied using three different sets of angular correlation of annihilation radiation (ACAR) and Compton scattering experimental data. ACAR data, measured with almost identical resolution, give both a similar anisotropy of the Fermi surface and a similar e-p enhancement factor inside this surface. However, as concerns a contribution of Umklapp components of valence-electron densities there are essential differences depending on experimental data. Due to a strong dependence of such densities on different theoretical approaches describing e-p correlations, it is suggested to perform additional, high statistics and resolution ACAR measurements for Mg and analyze them as suggested in the paper.