A Geometric Intrepertation for the Hans Lewy Operator Dimitrios E. Kalikakis — 2001 Δελτίο της Ελληνικής Μαθηματικής Εταιρίας
A characterization of regular saddle surfaces in the hyperbolic and spherical three-space. Kalikakis, Dimitrios E. — 2002 Abstract and Applied Analysis
On the curvature of nonregular saddle surfaces in the hyperbolic and spherical three-space. Kalikakis, Dimitrios E. — 2002 Abstract and Applied Analysis