Links to cryogenic institutions and physical data
Goddard Space Flight Centre: http://www.nasa.gov/centers/goddard/home/index.html
British Cryogenics Council: http://www.bcryo.org.uk/index.php
Cryogenic Society of America: http://www.cryogenicsociety.org/
NIST Physical reference data: http://www.nist.gov/pml/data/
NIST Thermodynamic properties of helium: http://srd.nist.gov/JPCRD/jpcrd40.pdf
NIST Properties of helium at saturated vapour pressure: http://www.nist.gov/srd/upload/jpcrd551.pdf
NIST Thermophysical properties of fluids: http://webbook.nist.gov/chemistry/fluid/