X. Catepillan et al., MULTIPLE CANONICAL DECOMPOSITIONS OF FAMILIES OF OPERATORS AND A MODEL OF QUASI-NORMAL FAMILIES, Proceedings of the American Mathematical Society, 121(4), 1994, pp. 1165-1172
A general method of canonical decompositions of several operator-value
d functions (operators) is presented. A model of a family of doubly co
mmuting quasinormal operators is constructed.