M. Kaltenbäck, H. Woracek, H. Winkler:
"Symmetric Relations of Finite Negativity";
Operator Theory: Advances and Applications, 162 (2005), S. 191 - 210.
http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC06587921
Projektleitung Heinz Langer:
RTN Analysis and Operators