%0 Journal Article %A Witbooi, P. J. %T Relative Homotopy in Relational Structures %J Canadian mathematical bulletin %D 2008 %P 310-320 %V 51 %N 2 %U http://geodesic.mathdoc.fr/articles/10.4153/CMB-2008-031-8/ %R 10.4153/CMB-2008-031-8 %F 10_4153_CMB_2008_031_8