Andrew Zisserman Joseph L. Mundy David A. Forsyth Jane Liu Nic Pillow Charlie Rothwell Sven Utcke Class-Based Grouping in Perspective Images. 183-188 1995 ICCV http://computer.org/proceedings/iccv/7042/70420183abs.htm db/conf/iccv/iccv1995.html#ZissermanMFLPRU95