James Q. Wilson and George L. Kelling in 1982, explored the impact that visible deterioration and neglect in neighborhoods have on behavior. Property maintenance was added as a CPTED strategy on par with surveillance, access control and territoriality. The Broken Windows theory may go hand in hand with CPTED. Crime is attracted to the areas that are not taken care of or abandoned. CPTED adds a pride of ownership feeling to the community. With no more "broken windows" in certain neighborhoods, crime will continue to decline and eventually fall out completely. Canadian academicians Patricia and Paul Brantingham published Environmental Criminology in 1981. According to the authors, a crime takes place when all of the essential elements are present. These elements consist of: a law, an offender, a target, and a place. They characterize these as "the four dimensions of crime", with environmental criminology studying the last of the four dimensions. British criminologists Ronald V. Clarke and Patricia Mayhew developed their "situational crime prevention" approach: reducing opportunity to offend by improving design and management of the environment. Criminologist Timothy Crowe developed his CPTED training programs. 1990s Criminology: An Interdisciplinary Approach (1990), was Jeffery's final contribution to CPTED. The Jeffery CPTED model evolved to one which assumes that The environment never influences behavior directly, but only through the brain. Any model of crime prevention must include both the brain and the physical environment. ... Because the approach contained in Jeffery's CPTED model is today based on many fields, including scientific knowledge of modern brain sciences, a focus on only external environmental crime prevention is inadequate as it ignores another entire dimension of CPTED – i.e., the internal environment. (Robinson, 1996) Crime Prevention Through Environmental Design (1991) by criminologist Tim Crowe provided a solid base for CPTED to move forward into the rest of the 1990s. From 1994 through 2002, Sparta Consulting Corporation led by Severin Sorensen, CPP managed the US Government's largest CPTED technical assistance and training program titled Crime Prevention Through Environmental Design (CPTED) in Public Housing Technical Assistance and Training Program, funded by the US Department of Housing and Urban Development. During this period Sorensen worked with Ronald V. Clarke and the Sparta team to develop a new CPTED Curriculum that used Situational Crime Prevention as an underlying theoretical basis for CPTED measures. A curriculum was developed and trained to stakeholders in public and assisted housing, and follow-up CPTED assessments