Citation: M. Kalka et al., THE EXPONENTIAL DECAY-RATE OF THE LOWER-BOUND FOR THE FIRST EIGENVALUE OF COMPACT MANIFOLDS, International journal of mathematics, 8(3), 1997, pp. 345-355
Citation: M. Kalka et Dg. Yang, ON NONPOSITIVE CURVATURE FUNCTIONS ON NONCOMPACT SURFACES OF FINITE TOPOLOGICAL TYPE, Indiana University mathematics journal, 43(3), 1994, pp. 775-804
Citation: M. Kalka et Dg. Yang, ON CONFORMAL DEFORMATION OF NONPOSITIVE CURVATURE ON NONCOMPACT SURFACES, Duke mathematical journal, 72(2), 1993, pp. 405-430