4Llobera M, Fabrega-Alvarez P, Parcero-Oubina C. Order in movement : a GIS approach to accessibility [ J ]. J Ar- chaeol Sci ,2011,38 (4) :843 - 851.
5Anifowose B,Chapman L,Lawler D,et al. Pipeline inter- diction and bridging in Nigeria: is a modification to the spatial connectivity matrix model required? [J]. J Transp Geography ,2011,19( 1 ) : 179 - 184.