Deckard Don: Complete sets of unitary invariants for compact and trace-class operators. In: Acta scientiarum mathematicarum, (28) 1-2. pp. 9-20. (1967)
Deckard Don; Pearcy Carl: On rootless operators and operators without logarithms. In: Acta scientiarum mathematicarum, (28) 1-2. pp. 1-7. (1967)