Generation of ring class fields by eta-quotients
  We generate ring class fields of imaginary quadratic fields in terms of the special values of certain eta-quotients, which are related to the relative norms of Siegel-Ramachandra invariants. These give us minimal polynomials with relatively small coefficients from which we are able to solve certain quadratic Diophantine equations concerning non-convenient numbers. 
Ja Kyung Koo, Dong Hwa Shin and Dong Sung Yoon
math.NT