1. Unbounded derivations of C∗-algebras, I;Bratteli;Comm. Math. Phys.,1975
2. Unbounded derivations of C∗-algebras, II;Bratteli;Comm. Math. Phys.,1976
3. Derivations in C∗-algebras;Chi,1976
4. Theory of Generalized Spectral Operators;Colojoarǎ,1968
5. Every n × n matrix Z with real spectrum satisfies ∥ Z − Z∗∥ ⩽ ∥ Z + Z∗ ∥ (log2 n + 0.038);Kahan,1973