OK, easing the thread back onto the tracks a little bit here, I offer a few publications on the subject of metrology and the SI system.
NIST Special Publication 330, 2001 Edition
The International System of Units (SI), Barry N. Taylor, Editor
This pub has a very complete list of SI Prefixes from yotta (10^24) to yocto (10^-24)
NIST Special Publication 811, 1995 Edition
Guide for the Use of the International System of Units (SI), Barry N. Taylor
NBS (NIST) Special Publication 447, March 1976
Weights and Measures Standards of the United States: A Brief History
This is an older publication printed before the National Bureau of Standards (NBS) was changed to the National Institute of Standards and Technology (NIST)
NIST Handbook 44, 2005 Edition
Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices
The Measure of all Things: The Seven-Year Odyssey and Hidden Error that Transformed the World, by Ken Alder, 2002, ISBN 0-7432-1675-X
This book describes the trek of Jean-Babtiste-Joseph Delambre and Pierre-Francois-Andre Machain to establish the meter as one ten-millionth of the distance from the North Pole to the equator.
I was surprised to learn that 2.54 cm/in is now an EXACT conversion for length between the metric and the English/SAE/Imperial system. Knowing the the two systems as I had, I knew that the exact conversion HAD to be some irrational number. But with the push toward metric and knowing that in some disciplines such as machining, if you're metric, stay that way; if English, stay that way. Don't try to convert from one to another to use, for instance, a non-electronic micrometer in an alternate system. To use conversion tables, you'll automatically induce error.
That change in the cm/in conversion has really screwed up things in the U.S. where land surveying has always used the old conversion and STILL DOES. To switch to the new conversion factor, land surveys will shift by inches, feet or more, causing all kinds of hate and discontent!
Dean