2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/27535Recently Mishonov (Phys. Rev. B {\bf 50}, 4009 (1994)) suggested to measure the Cooper-pair effective mass using current-induced contact potential difference in superconductors. In this Comment it is shown that actual experiments can be substantially simplified.Condensed Mattertext