Since creating the new BarhamSoftware website, downloads are now broken down into the areas of interest:
The NIST Reference on Constants, Units, and Uncertainty
The Metric System- an online lesson from a Math course offered by R. H. Logan, Instructor of Chemistry, Dallas County Community College District, North Lake College.
Basic & Derived SI Units - table from TechExpo that lists dimensions, SI units, and symbols.
Dictionary of Units - University of Exeter, Centre for Innovation in Mathematics Teaching
Roanoke Valley Governor's School, VA (on Significant Digits)
Diamond Bar High School, CA (on Significant Digits)
World of Chemistry: The Home
Page of Ralph Logan (on Significant Digits)
Science Hypermedia, Inc. (on Significant Digits)