Konrad Fialkowski Mieczyslaw Muraszkiewicz Alicja B. Tolwinska Methodology of world clearinghouse activity. 21-25 1981 17 Inf. Process. Manage. 1 http://dx.doi.org/10.1016/0306-4573(81)90038-8 db/journals/ipm/ipm17.html#FialkowskiMT81