[6] Enochs, E.E., & Jenda, O. M .G. (2000). Relative homological algebra. De Gruyter Expositions in Mathematics, 30, Walter de Gruyter & Co., Berlin.
https://doi.org/10.1515/9783110803662
[8] Garkusha, G. A., & Generalov, A. I. (1999). Duality for categories of nitely presented modules. (Russian) Algebra i Analiz, 11(6), 139-152. translation in St. Petersburg Math. J, 11(6) (2000), 1051-1061.
[14] Lianggui, F. (1997). Essential extensions, excellent extensions and finitely presented dimension. Acta Mathematica Sinica, 13(2), 231-238.
https://doi.org/10.1007/BF02559962
[21] Xue, W. (1996). On almost excellent extension. Algebra Colloq, (3), 125-134.