00311nam a2200097Ia 450000500170000000800410001705000150005810000160007324500900008926000340017920251229191001.0251229s9999    xx            000 0 und d  aQK 911 .B7  aHarper J.L. 4aThe biology of weedsb A symposium of the British Ecological society OxfordcL Harper  aOxfordb Blackwell Pub; 1960.