1. Burstall, R.M.: Proving properties of programs by structural induction. Comput. J. 12, 41?48 (1969)
2. Burstall, R.M.: Some techniques for proving correctness of programs which alter data structures. In: Machine intelligence, Vol. 7 (B. Meltzer, D. Michie, eds.), pp. 23?50. Edinburgh: University Press 1972
3. Burstall, R.M.: Program proving as hand simulation with a little induction. In: Proc. IFIP Congress 1974, pp. 308?312. Amsterdam: North-Holland 1974
4. Floyd, R.W.: Assigning meanings to programs. In: Proc. Symposium in Applied Mathematics 19 (J.T. Schwartz, ed.), pp. 19?32. Providence, R.I.: AMS 1967
5. Hoare, C.A.R.: Proof of correctness of data representations. Acta Informat. 1, 271?281 (1972)