1. Chellas, Brian F., ‘Basic Conditional Logic’, Dittographed, University of Pennsylvania, 1970.
2. Føllesdal, Dagfinn, and Hilpinen, Risto, ‘Deontic Logic: An Introduction’, in Deontic Logic: Introductory and Systematic Readings (ed. by Risto Hilpinen ), D. Reidel Publishing Company, Dordrecht, 1971, pp. 1–35.
3. Gabbay, Dov M., ‘A General Theory of the Conditional in Terms of a Ternary Operator’, Theoria 38 (1972), 97–104.
4. Hansson, Bengt, ‘An Analysis of Some Deontic Logics’, Nôus 3 (1969), 373–398.
5. Hansson, Bengt, ‘An Analysis of Some Deontic Logics’, Deontic Logic: Introductory and Systematic Readings (ed. by Risto Hilpinen ), D. Reidel Publishing Company, Dordrecht, 1971, pp. 121–147.