Talbi, M. E., e D. Benayat. “<b>The Homotopy Exact Sequence of a Pair of graphs</b> - Doi: 10.4025/actascitechnol.V35i4.15775”. Acta Scientiarum. Technology, vol. 35, nº 4, maio de 2013, p. 733-8, doi:10.4025/actascitechnol.v35i4.15775.