[1] Aldrich S T, Enochs E E, Garc´?a Rozas J R, Oyonarte L. Covers and envelopes in Grothendieck categories: Flat covers of complexes with applications. J Algebra, 2001, 243: 615–630
[2] Aldrich S T, Enochs E E, Jenda O M G, Oyonarte L. Envelopes and covers by modules of finite injective and projective dimensions. J Algebra, 2001, 242: 447–459
[3] Asensio M J, Martinez H J. Flat envelopes in commutative rings. Israel J Math, 1988, 62(1): 123–128
[4] Auslander M, Smalø S O. Preprojective modules over Artin algebras. J Algebra, 1980, 66(1): 61–122
[5] Bican L, El Bashir R, Enochs E E. All modules have flat covers. Bull London Math Soc, 2001, 33: 385–390
[6] Chen J L, Ding N Q. A note on existence of envelopes and covers. Bull Austral Math Soc, 1996, 54: 383–390
[7] Ding N Q. On envelopes with the unique mapping property. Comm Algebra, 1996, 24(4): 1459–1470
[8] Eklof P C, Trlifaj J. How to make Ext vanish. Bull London Math Soc, 2001, 33(1): 41–51
[9] Enochs E E. Flat covers and flat cotorsion modules. Proc Amer Math Soc, 1984, 92(2): 179–184
[10] Enochs E E. Injective and flat covers, envelopes and resolvents. Israel J Math, 1981, 39: 189–209
[11] Enochs E E, Jenda O M G, Torrecillas B, Xu J. Torsion Theory with Respect to Ext. Research Report 98–11, May, Department of Mathematics, University of Kentucky, 1998
[12] Enochs E E, Jenda O M G. Relative Homological Algebra. Berlin, New York: Walter de Gruyter, 2000
[13] Enochs E E, Jenda O M G, Lopez-Ramos J A. The existence of Gorenstein flat covers. Math Scand, 2004, 94: 46–62
[14] Enochs E E, Oyonarte L. Covers, Envelopes and Cotorsion Theories. New York: Nova Science Publishers, Inc, 2002
[15] Fieldhouse D J. Character modules, dimension, and purity. Glasgow Math J, 1972, 13: 144–146
[16] Garc´?a Rozas J R. Covers and Envelopes in the Category of Complexes of Modules. Boca Raton, FL: Chapman & Hall/CRC, 1999
[17] Geng Y X. The P-cotorsion dimensions of modules and rings. Acta Math Sci, 2010, 30B(4): 1029–1043
[18] G¨obel R, Trlifaj J. Approximations and Endomorphism Algebras of Modules. Berlin, New York: Walter de Gruyter, 2006
[19] Lu B, Liu Z K. IFP-flat modules and IFP-injective modules. Comm Algebra, 2012, 40: 361–374
[20] Mao L X, Ding N Q. Relative FP-projective modules. Comm Algebra, 2005, 33(5): 1587–1602
[21] Mao L X, Ding N Q. Notes on cotorsion modules. Comm Algebra, 2005, 33(1): 349–360
[22] Trlifaj J. Covers, Envelopes, and Cotorsion Theories. Lecture Notes for the Workshop. Homological Methods in Module Theory. Cortona, September 10–16, 2000
[23] Xu J. Flat Covers of Modules. Lecture Notes in Math, 1634. Berlin, Heidelberg, New York: Springer-Verlag, 1996 |