1. Spectrum for a solvable Lie algebra of operators;Beltiţă;Stud. Math.,1999
2. Commutative Algebra;Bourbaki,1971
3. Projective spectrum and cyclic cohomology;Cade;J. Funct. Anal.,2013
4. Joint spectra of matrices;Cho;Sci. Rep. Hirosaki Univ.,1979
5. Theory of Generalized Spectral Operators;Colojoařa,1968