International System of Units
Metric system - Wikipedia
Gal (unit) - Wikipedia
The evolution of the International System of Units
Orders of magnitude (mass) - Wikipedia
System of units of measurement - Wikipedia
French units of measurement - Wikipedia
Length - Wikipedia, PDF, Length
Data Units – Wiki-WebPerfect
International System of Units, Measurement, Conversion & History
Unit of measurement - Wikipedia
Ampere - Wikipedia
Hindu units of time - Wikipedia
United States customary units - Wikipedia