. . . . . . "m_a" . . . . . . . . . . . . . . . . "The \"Atomic Mass\" is the mass of a specific isotope, most often expressed in unified atomic mass units." . . . . . . . . . . . . . . . . . . . . . . . . . . "Atomic Mass"@en . . "http://en.wikipedia.org/wiki/Atomic_mass"^^ . "http://www.iso.org/iso/catalogue_detail?csnumber=31895"^^ . . . .