{"id":"001211241","type":"book","title":"Rings and sectors: a computer package for spatial analysis ; with examples from Oldeholtwolde and Gönnersdorf","publisher":"Universa","publisher-place":"Wetteren","pages":"20-35","container-title":"Helinium, 33 (1993","author":[{"family":"Boekschoten","given":"Gijsbert R."}],"issued":{"raw":"1993"}}