1. To Walk or Not to Walk? The Hierarchy of Walking Needs;Alfonzo;Environmental Behavior,2005
2. Travel Choices in Pedestrian Versus Automobile Oriented Neighborhoods;Cervero;Transport Policy,1996
3. Chu , S. C. H. 2005 When and Why Do People Walk in the City: The Influence of Urban Elements on Time-Pattern of Pedestrian Movement Proceedings of the Sixth International Walk 21 Conference .
4. City of Cambridge 2000 Cambridge Pedestrian Plan http://www.cambridgema.gov/~/media/Files/CDD/Transportation/Pedestrian/ped_plan_2000.ashx
5. City of Portland 1998 Portland Pedestrian Master Plan http://www.portlandoregon.gov/transportation/article/90244