=LDR 22 4500 =001 1633 =082 04$a551.7 WAL =100 1\$aWalden, J. =245 10$aEnvironmental magnetism: a practical guide =260 \\$bQuaternary Research Association,$c1999 =650 \0$aReference =700 1\$aOldfield, Frank =852 \\$bFreeman Library$h551.7 WAL$zNot located