Central business districts

found: Haikalis, G. Auto-free zones in CBDs and an example for lower Manhattan, 1974.

found: Seger, M. Istanbul's backbone--a chain of central business districts (CBDs), 2012.

found: Encouraging development through the use of rating options in Melbourne's central activities district, 1984.

found: Streets for people : a pedestrian strategy for the Central Activities District of Melbourne, 1985.

found: About.com Geography website, Mar. 28, 2013(The CBD or Central Business District is focal point of a city. It is the commercial, office, retail, and cultural center of the city and usually is the center point for transportation networks. ... As cities grew and developed, CBDs became fixed location where retail and commerce took place.)

found: Wikipedia, Mar. 28, 2013(Central business district. A central business district (CBD, also called a central activities district) is the commercial and often geographic heart of a city. In the United States of America and Canada this part of a city is commonly referred to as "downtown" or "city center ("centre" in Canada)". "City centre" is commonly used in Ireland and the United Kingdom. The term CBD or Central Business District is the central district of a city, usually typified by a concentration of retail and office buildings. The term city place is similar to CBD in that both serve the same purpose for the city, and both are marked by a higher-than-usual urban density as well as often having the tallest buildings in a city. City centre differs from downtown in that the latter can be geographically located anywhere in a city, while a city centre is generally located near the geographic heart of the city.)