=LDR 22 4500 =001 5213 =082 04$a526.022 JOH =100 1\$aJohnston, R. J. =245 10$aSpatial structures: introducing the study of spatial systems in human geography =260 \\$aLondon :$bMethuen,$c1973 =650 \0$aBooks =852 \\$bFreeman Library$h526.022 JOH