[1] B. Aupetit: A Primer on Spectral Theory. Springer-Verlag, , 1991. MR 1083349 | Zbl 0715.46023

[2] B. A. Barnes, G. J.  Murphy, M. R. F. Smyth and T. T.  West: Riesz and Fredholm Theory in Banach Algebras. Pitman, Boston-London-Melbourne, 1982. MR 0668516

[3] P. G. Dixon: Spectra of left approximate identities in Banach algebras. Bull. London Math. Soc. 19 (1987), 169–173. DOI 10.1112/blms/19.2.169 | MR 0872133 | Zbl 0591.46041

[4] J. J. Grobler and H.  Raubenheimer: Spectral properties of elements in different Banach algebras. Glasgow Math.  J. 33 (1991), 11–20. DOI 10.1017/S0017089500007989 | MR 1089949

[5] R. E.  Harte: The exponential spectrum in Banach algebras. Proc. Amer. Math. Soc. 58 (1976), 114–118. DOI 10.1090/S0002-9939-1976-0407603-5 | MR 0407603 | Zbl 0338.46043

[6] R. E. Harte: Fredholm theory relative to a Banach algebra homomorphism. Math.  Z. 179 (1982), 431–436. DOI 10.1007/BF01215344 | MR 0649045 | Zbl 0479.47032

[7] R. E. Harte: Fredholm, Weyl and Browder theory. Proc. Royal Irish Academy Vol.  85A, 1985, pp. 151–176. MR 0845539 | Zbl 0567.47001

[8] R. E.  Harte: Invertibility and Singularity for Bounded Linear Operators. Marcel Dekker, New York-Basel, 1988. MR 0920812 | Zbl 0636.47001

[9] R. E.  Harte: On rank one elements. Studia Math. 117 (1995), 73–77. DOI 10.4064/sm-117-1-73-77 | MR 1367694 | Zbl 0837.46036

[10] R. E. Harte and H.  Raubenheimer: Fredholm, Weyl and Browder theory III. Proc. Royal Irish Academy Vol.  95A, 1995, pp. 11–16. MR 1369040

[11] R. E.  Harte and A. W. Wickstead: Boundaries, hulls and spectral mapping theorems. Proceedings of the Royal Irish Academy Vol 81A, 1981, pp. 201–208. MR 0654819

[12] V.  Kordula and V.  Müller: Axiomatic theory of spectrum. Studia Math. 119 (1996), 109–128. MR 1391471

[13] L.  Lindeboom and H. Raubenheimer: A note on the singular spectrum. Extracta Math. 13 (1998), 349–357. MR 1695568

[14] A.  Lebow and M.  Schechter: Semigroups of operators and measures of noncompactness. J.  Funct. Anal. 7 (1971), 1–26. DOI 10.1016/0022-1236(71)90041-3 | MR 0273422

[15] M.  Mbekhta and V.  Müller: On axiomatic theory of spectrum II. Studia Math. 119 (1996), 129–147. DOI 10.4064/sm-119-2-129-147 | MR 1391472

[16] H. du T.  Mouton: On inessential ideals in Banach algebras. Quaestiones Mathematicae 17 (1994), 59–66. DOI 10.1080/16073606.1994.9632217 | MR 1276008 | Zbl 0818.46053

[17] T.  Mouton and H.  Raubenheimer: More Fredholm theory relative to a Banach algebra homomorphism. Proceedings of the Royal Irish Academy Vol. 93A, 1993, pp. 17–25. MR 1241836

[18] T.  Mouton and H.  Raubenheimer: On rank one and finite elements in Banach algebras. Studia Math. 104 (1993), 211–219. DOI 10.4064/sm-104-3-211-219 | MR 1220661

[19] J.  Puhl: The trace of finite and nuclear elements in Banach algebras. Czechoslovak Math. J. 28(103) (1978), 656–676. MR 0506439 | Zbl 0394.46041

[20] M. R. F.  Smyth: Riesz theory in Banach algebras. Math.  Z. 145 (1975), 145–155. DOI 10.1007/BF01214779 | MR 0394210 | Zbl 0298.46049

[21] A. E.  Taylor and D. C.  Lay: Introduction to Functional Analysis. 2nd ed. John Wiley, New York, 1980. MR 0564653

[22] W. .Zelazko: Axiomatic approach to joint spectra I. Studia Math. 64 (1979), 249–261. DOI 10.4064/sm-64-3-249-261 | MR 0544729 | Zbl 0426.47002