kgm : An incorrect symbol for the kilogram (see below). The correct symbol is kg. In engineering, "kgm" is sometimes used to distinguish "kilogram mass" from "kilogram force" (kgf). This practice is not recommended
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}