1. Parking in Boston,2001
2. Bus+Bahn, 1977. Kommentar überflüssig, p. 2.
3. An Assessment of the Likely Impact of Changes in Short Term Metered Parking Prices on Parkers in the Central City Area;Clark,1993
4. Policies to Manage Parking in the Central City Area;Clark,1993
5. Colliers International, 2003. North America CBD Parking Rate Survey, The Parking Professional, September, pp. 27–31.