References
S. C. Althoen, A van Kampen theorem. J. Pure Appl. Algebra6, 41–47 (1975).
R. Brown, Groupoids and van Kampen's theorem. Proc. London Math. Soc. (3)17, 385–401 (1967).
R.Brown, Higher-dimensional group theory, in Low-dimensional topology. Proc. Bangor Symp. 1979, Ed. R. Brown and T. L. Thickstun, London Math. Soc. Lecture Note Series48, 215–238 (1982).
J. C. Chipman, Van Kampen's theorem forn-stage covers. Trans. Amer. Math. Soc.192, 357–370 (1974).
R. H. Crowell, On the van Kampen theorem. Pacific J. Math.9, 43–50 (1959).
P. J.Higgins, Categories and groupoids. van Nostrand Reinhold Mathematical Studies 32, 1971.
A.Razak Salleh, Union theorems for double groupoids and groupoids; some generalisations and applications. Ph.D. Thesis, University of Wales (1976).
A. I. Weinzweig, The fundamental group of a union of spaces. Pacific J. Math.11, 763–776 (1961).
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This paper was written while the second author was on sabbatical leave at Bangor in 1982/83 with support from the Universiti Kebangsaan Malaysia.
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Brown, R., Salleh, A.R. A van Kampen theorem for unions of non-connected spaces. Arch. Math 42, 85–88 (1984). https://doi.org/10.1007/BF01198133
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DOI: https://doi.org/10.1007/BF01198133