From Statsitical And Thermal Physics (Reif. international edition 1985)
160 page. (5.4.4)
S(T,V;√) = √[∫{cv(T`)/T`}dT` + Rln(V) - Rln(√) + constant]
(integral is from T0 to T , cv is specific heat)
This is a entropy of system for temperature 'T' , Volume 'V' , Moles '√' <--...