It can be found by searching for "mini refprop" on the NIST website or through university resources. 2. Pricing and Licensing for Full Versions
It provides the most accurate equations of state available. refprop 91 free
For students or researchers on a budget, the mini-REFPROP download provides the core functionality needed for basic thermodynamic calculations without the cost of the full industrial database. It can be found by searching for "mini