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2. Causality and Modern Science;Bunge,1979
3. The Effectiveness of Automatic Protection in Reducing Accident Frequency and Severity at Public Grade Crossings in California. Federal Highway Administration;California P.U.C.,1975
4. The planning of observational studies of human populations (with discussion);Cochran;Journal of the Royal Statistical Society, Series A,1965
5. Railroad grade crossing research activities;Coleman,1982