Resolution 8 of the 12th CGPM (1964)
SI prefixes femto and atto
The 12th Conférence Générale des Poids et Mesures (CGPM),
decides to add to the list of prefixes for the formation of names of multiples and submultiples of units, adopted by the
New prefixes were added by the 15th CGPM in 1975 (Resolution 10).