Stanilov-Tsankov-Videv theory.
Brozos-Vázquez, Miguel; Fiedler, Bernd; García-Río, Eduardo; Gilkey, Peter; Nikčević, Stana; Stanilov, Grozio; Tsankov, Yulian; Vázquez-Lorenzo, Ramón; Videv, Veselin — 2007
SIGMA. Symmetry, Integrability and Geometry: Methods and Applications [electronic only]