classifer by allen burry for cement mill. Spatial Differentiation and Price Discrimination in the Cement Industry. 6 Aug 2013 ... geographically to charge higher mill prices to nearby customers. ... We thank Jim Adams, Simon Anderson, Allan Collard-Wexler, Abe Dunn, .... differentiated in product space (e.g. Berry, Levinsohn, and Pakes (1995 ...