1. Back, R.J.R., On the correctness of refinement steps in program development (Ph.D. thesis), Report A-1978-4, Dept. of Computer Science, University of Helsiniki, 1978.
2. Back, R.J.R., Correctness Preserving Program Refinements: Proof Theory and Applications, Mathematical Center Tracts 131, Mathematical Centre, Amsterdam 1980.
3. R.J.R. Back, A Calculus of Refinements for Program Derivations, Acta Informatica vol. 25, no 6, 1988, 593–624.
4. Back, R.J.R., Procedural abstraction in the refinement calculus, Reports on Computer Science and Mathematics 55, Abo Akademi 1987.
5. Back,R.J.R., Refining atomicity in parallel programs, Reports on Computer Science and Mathematics 57, Abo Akademi 1988.