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2. Bounds on derivation lengths from termination proofs;Cichon,1990
3. Termination orderings and complexity characterizations;Cichon,1993
4. Termination proofs by multiset path orderings imply primitive recursive derivation lengths;Hofbauer,1990
5. Ordinal recursion in partial systems of number theory;Parsons;Notices Amer. Math. Soc.,1966