[1]

M. Dadarlat and S. Eilers. Approximate homogeneity is not a local property. J. Reine Angew. Math., 507:1-13, 1999.

[2]

M. Dadarlat. Nonnuclear subalgebras of AF algebras. Amer. J. Math., 122(3):581-597, 2000.

[3]

P. Friis and M. Rørdam. Approximation with normal operators with finite spectrum, and an elementary proof of a Brown-Douglas-Fillmore theorem. to appear in Pacific J. Math, 1998.

[4]

P. Friis. Normal elements with finite spectrum in C*-algebras of real rank zero. PhD thesis, University of Toronto, 1999.

[5]

G. K. Pedersen. Extensions of C*-algebras. In Operator algebras and quantum field theory (Rome, 1996), pages 1-35. Internat. Press, Cambridge, MA, 199?

[6]

Gert K. Pedersen. Pullback and pushout constructions in C*-algebra theory. J. Funct. Anal., 167(2):243-344, 1999.