Extended temperature range (40-400K) PSP model (called PSP-E) is now available. References: http://pspmodel.asu.edu/lowtemp.htm. Contact information: gildenblat@asu.edu.
In-depth discussion of PSP, PSP-SOI, MOSVAR, R3, and several other compact models can be found in www.springer.com/978-90-481-8613-6.