1. Auslander, M., Bridger, M.: Stable Module Theory, Mem. Am. Math. Soc., 94, Amer. Math. Soc., Providence, RI, 1969
2. Auslander, M., Buchweitz, R. O.: The homological theory of maximal Cohen—Macaulay approximations. Mém Soc. Math. Fr., Nouv. Sr., 38, 5–37 (1989)
3. Bennis, D., Ouarghi, K.: $${\cal X}$$-Gorenstein projective modules. Int. Math. Forum, 5, 487–491 (2010)
4. Bravo, D., Gillespie, J.: Absolutely clean, level, and Gorenstein AC-injective complexes. Commun. Algebra, 44, 2213–2233 (2016)
5. Bravo, D., Gillespie, J., Hovey, M.: The stable module category of a general ring. arxiv:1405.5768, 2014