Characterizations of flowchartable recursionsS.A. WalkerH.R. Strong1973Journal of Computer and System SciencesPaper
Characterizations of flowchartable recursions short versionS.A. WalkerH.R. Strong1972STOC 1972Conference paper
Properties preserved under recursion removalH.R. StrongS.A. Walker1972ACM Conference on Proving Assertions about Programs 1972Conference paper