1. Hierarchical skills in typewriting;Fendrick;Journal of Educational Psychology,1937
2. Digram keying times for typists;Fox;Ergometrics,1964
3. Keystroke timing in skilled typing;Gentner,1983
4. Digraph frequency effects in skilled typing;Grudin,1982
5. An exploration of psycholinguistic units in initial reading;Hanson,1968