[1] M. Alp, Actor of crossed modules of algebroids, Proceedings of the 16th Int. Conf. Jangjeon Math. soc., 16 (2005) 6–15.
[2] M. Alp, Pullback crossed modules of algebroids, Iran. J. Sci. Technol. Trans. A Sci., 32 no. 1 (2008) 1–5.
[3] M. Alp, Pullbacks of profinite crossed modules and CAT1-profinite groups, Algebras Groups Geom., 25 no. 2 (2008) 215–221.
[4] M. Alp and B. Davvaz, Crossed polymodules and fundamental relations, Politehn. Univ. Bucharest Sci. Bull. Ser. A Appl. Math. Phys., 77 no. 2 (2015) 129–140.
[5] M. Alp and Ö. Gürmen, Pushouts of profinite crossed modules and cat 1-profinite groups, Turkish J. Math., 27 (2003) 539–548.
[6] Z. Arvasi and T. porter, Freeness conditions for 2-crossed modules of commutative algebras, Appl. Categ. Structures, 6 (1998) 455–471.
[7] Z. Arvasi and E. Ulualan, On algebraic models for homotopy 3-types, J. Homotopy Relat. Struct.,1 no. 1 (2006) 1–27.
[8] H. J. Baues, Combinatorial homotopy and 4-dimensional compexes, Walter de Gruyter, Berlin, De Gruyter expositions in Mathematics, 1991.
[9] R. Brown and G. H. Mosa, Double categories, R-categories and crossed modules, U. C. N. W. maths. preprint, 88 no. 11 (1988) 1–18.
[10] S. D. Comer, Extension of polygroups by polygroups and their representations using colour schemes, Lecture notes in Meth. 1004 (1982) 91–103.
[11] D. Conduché, Modules croisés généralisés de longueur 2, J. pure Applied Algebra, 34 (1984) 155–178.
[12] P. Corsini, Prolegomena of hypergroup theory, Supplement to Riv. Mat. Pura Appl., Aviani Editore, Tricesimo, 1993 215 pp.
[13] B. Davvaz, Isomorphism theorems of polygroups, Bull. Malays. Math. Sci. Soc. (2), 33 no. 3 (2010) 385-392.
[14] M. A. Dehghanizadeh, B. Davvaz and M. Alp, On crossed polysquares and fundamental relations, 13th Algebraic Hyperstructures and its Applications (AHA2017) 24-27 july, Istanbul-Turkey, (2017) and appeared in: Sigma J. Eng. & Nat. Sci., 9 no. 1 (2018) 1–16.
[15] M. A. Dehghanizadeh, B. Davvaz and M. Alp, On crossed polysquare version of homotopy kernels, Journal of Mathematical Extension, 16 no. 3 (2022) 1–37.
[16] D. Freni, Une note sur le coeur d’un hypergroupe et sur la clôture transitive β∗ de β, Riv. Math. Pura Appl., 8 (1991) 153–156.
[17] D. Guin-Walery and J. L. Loday, Obstruction á 1’excision en k-théories algébrique, In E. M. Friedlander, M. R. Stein (eds.), Evanston conf. On Algebraic k-Theory (1980), (Lect. Notes Math. 854) Springer, Berlin, Heidelberg, New York, (1981) 179–216.
[18] F. J. Korkes and J. Porter, Profinite crossed modules, U. C. N. W pure mathematics preprint, 86 no. 11 (1986).
[19] M. Koskas, Groupoids, demi-groups et hypergroups, J. Math. Pures Appl., 49 (1970) 155–192.
[20] V. Leoreanu-Fotea, The heart of some important classes of hypergroups, Pure math. Appl., 9 (1998) 351–360.
[21] J. L. Loday, Spaces with finitely many non-trivial homotopy groups, J. Appl. Algebra, 24 (1982) 179–202.
[22] K. Norrie, Actions and automorphisms of crossed modules, Bull. Soc. Math. France, 118 (1990) 129–146.
[23] T. Vougiouklis, Hyperstructures and their representations, Hadronic Press, Inc, 115, palm Harber, USA, 1994.
[24] J. H. C. Whitehead, Combinatorial homotopy II, Bull. Amer. Math. Soc., 55 (1949) 453–496.
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