=LDR 22 4500 =001 1333 =082 04$a550 YOX =100 1\$aYoxall, W. H. =245 10$aDynamic models in earth-science instruction =260 \\$aLondon :$bCambridge University Press,$c1983 =650 \0$aBooks =852 \\$bFreeman Library$h550 YOX