"Microgram Per Kilogram"@en . . "J33" . . . . . . . "mass ratio as 0.000000001-fold of the SI base unit kilogram divided by the SI base unit kilogram"^^ . "\u03BCg/kg" . "1e-09"^^ . . "ug.kg-1"^^ . "mass ratio as 0.000000001-fold of the SI base unit kilogram divided by the SI base unit kilogram" . . . "ug/kg"^^ . "0112/2///62720#UAA083" .