The EOS-80 seawater properties are obsolete; they have been superseded by
the International Thermodynamic Equation Of Seawater - 2010 (TEOS-10).
The official site for the thermodynamic properties of seawater is www.TEOS-10.org.
Reference
Unesco, 1981: The Practical Salinity Scale 1978 and the International Equation of State of
Seawater 1980. Unesco technical papers in marine science 36, 25pp.