TY - PROGRESS IN GEOGRAPHY A1 - T1 - Y1 - 1989-01-24 JF - PROGRESS IN GEOGRAPHY JO - PROGRESS IN GEOGRAPHY SP - 60 EP - 63 VL - 8 IS - 1 UR - http://www.progressingeography.com N1 - 10.11820/dlkxjz.1989.01.015 ER -