M. P. Unterweger, D. D. Hoppes, and F. J. Schima
This database is a table of the half lives of 65 important radionuclides measured primarily with ionization chambers by the Radioactivity Group of NIST. The included half lives range from 10 minutes to 60.7 years.
J. S. Coursey, D. J. Schwab, and R. A. Dragoset
This database contains the isotopic compositions or abundances of those elements which have characteristic terrestrial compositions. Atomic weights and relative atomic masses are also available for elements 1 through 112, 114 & 116.