Bibliography: 
1. 
Paul Hofstee: Actual Space Use Map of Enschede - 
Urban Land Use Inventory with Photo Interpretation, 
The ITC-Journal, 1976 - 5, page 451. 
Kari A, Lautso: The Use of Aerial Photography in 
Traffic Studies, Especially in Pedestrian and Park- 
ing Surveys. Center for Urban and Regional Studies, 
Helsinki University of Technology, Finland, 
Publication B 17, ISBN 951-751-277-5 (Finnish with 
English summary).