[1] B. Banaschewski, Injectivity and essential extensions in equational classes of algebras, Queen's Papers Pure Appl. Math. 25 (1970), 131-147.
[2] S. Bulman-Fleming, Subpullback flat $S$-posets need not be subequlizer flat, Semigroup Forum, 78(1) (2009), 27-33.
[3] S. Bulman-Fleming, D. Gutermuth, A. Gilmour, and M. Kilp, Flatness properties of $S$-posets, Comm. Algebra {34}(4) (2006), 1291-1317.
[4] S. Bulman-Fleming and V. Laan, Lazard's theorem for $S$-posets, Math. Nachr. {278}(15) (2005), 1743-1755.
[5] S. Bulman-Fleming and M. Mahmoudi, The category of S-posets, Semigroup Forum {71}(3) (2005), 443-461.
[6] D. Dikranjan and W. Tholen, Categorical structure of closure operators, with applications to topology, algebra, and discrete mathematics", Mathematics and Its Applications, Kluwer Academic Publ., 1995.
[7] M.M. Ebrahimi, M. Haddadi, and M. Mahmoudi, Injectivity in a category: an overview of well behaviour theorems, Algebra, Groups, and Geometries 26 (2009), 451-472.
[7] M.M. Ebrahimi, M. Haddadi, and M. Mahmoudi, Injectivity in a category: an overview on smallness conditions, Categ. General Alg. Struct. Appl. 2(1) (2014), 83-112.
[8] M. Mehdi Ebrahimi and M. Mahmoudi, The category of $M$-sets, Ital. J. Pure Appl. Math. {9} (2001), 123-132.
[9] M. Mehdi Ebrahimi, M. Mahmoudi, and H. Rasouli, Banaschewski's theorem for S-posets: regular injectivity and completeness, {Semigroup Forum} {80}(2) (2010), 313-324.
[10] S.M.-Fakhruddin, On the category of S-posets, Acta Sci. Math. (Szeged)} {52} (1988), 85-92.
[11] M. Kilp, U. Knauer, and A. Mikhalev, Monoids, Acts and Categories, Walter de Gruyter, Berlin, New York, 2000.
[12] H. Rasouli, Categorical properties of regular monomorphisms of $S$-posets, Europ. J. Pure Appl. Math. {7}(2) (2014), 166-178.
[13] L. Shahbaz and M. Mahmoudi, Various kinds of regular injectivity for $S$-posets, Bull. Iranian Math. Soc. {40}(1) (2014), 243-261.
[14] L. Shahbaz and M. Mahmoudi, Injectivity of $S$-posets with respect to down closed regular monomorphisms, Semigroup Forum, Published online (2015) DOI:10.1007/s00233-014-9676-y.
[15] X. Shi, On flatness properties of cyclic $S$-posets, {Semigroup Forum} {77}(2) (2008), 248-266.
[16] X.P. Shi, Z. Liu, F.G. Wang, and S. Bulman-Fleming, Indecomposable, projective and flat $S$-posets, Comm. Algebra {33}(1) (2005), 235-251.
[17] L.A.-Skornjakov, On the injectivity of ordered left acts over monoids, Vestnik Moskov. Univ. Ser. I Math. Mekh. (1986), 17-19 (in Russian).
[18] W. Tholen, Injective objects and cogenerating sets, J. Algebra {73}(1) (1981), 139-155.
[19] X. Zhang, Regular injectivity of S-posets over Clifford pomonoids, Southeast Asian Bull. Math. {32} (2007), 1007-1015.
[20] X. Zhang and V. Laan, On homological classification of pomonoids by regular weak injectivity properties of S-posets, Cent. Eur. J.Math. {5}(1) (2007), 181-200.
)