Dr. Steve Rapp, 2005
Rules for Writing SI Units
14. The SI units names that contain a ratio or
quotient, use the word per rather than the
15. Power of units use the modifier squared
or cubed after the unit name.
16. Symbols and unit names should not be
mixed in the same expression. NOT:
17. SI prefix symbols are written is regular
upright type (no hyphen between the prefix
and the unit symbol).