Gray, James N.; Harrison, Michael A. On the covering and reduction problems for context-free grammars. (English) Zbl 0259.68035 J. Assoc. Comput. Mach. 19, 675-698 (1972). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 2 ReviewsCited in 22 Documents MSC: 68Q45 Formal languages and automata PDFBibTeX XMLCite \textit{J. N. Gray} and \textit{M. A. Harrison}, J. Assoc. Comput. Mach. 19, 675--698 (1972; Zbl 0259.68035) Full Text: DOI