1. ABT Associates Inc., a variety of games for social studies including The Potlatch Package, a unit on the Kwakiutl Indians of the Pacific Northwest; Neighborhood Game, a simulation of urban growth with four different ethnic units; Transportation, involving time, money and distance with different transport methods; 55 Wheeler Street. Cambridge, Massachusetts, 02138, U.S.A
2. Armstrong , R. H. R. Taylor , J. L. 1970 Instructional Simulation Systems in Higher Education . Cambridge Monographs on Education, No. 2
3. Operational Games for Geographers;Blouet;Journal of Geography,1971