Rogers, J. R. 1962. "A formula for predicting the comprehension level of material to be presented orally." The journal of educational research 56:218-220.

Rothkopf, E. Z. 1972. "Structural text features and the control of processes in learning written materials," In Language comprehension and the acquisition of knowledge, eds. R.O. Freedle and J. B. Carroll. Washington, DC: Winston.

Rothkopf, E. Z. 1977. "Text difficulty predicted from functional chaining in short term memory." Abstracts of papers and symposia. American Educational Research Association annual meeting, Washington, D.C.

Rumelhart, D. E. 1984. "Understanding understanding." In Understanding reading comprehension: cognition, language, and the structure of prose, ed. J. Flood. Newark, DE: International Reading Association.

Russell, S. N. 1973. "Error pattern relationship of developmental readers and functionally illiterate adults." Ed.D. dissertation. Oklahoma State University.

School Renaissance Institute. 1999. ZPD guidelines: Helping students achieve optimum reading growth. Madison, WI: School Renaissance Institute, Inc.

School Renaissance Institute. 2000. The ATOS readability formula for books and how it compares to other formulas. Madison, WI: School Renaissance Institute, Inc.

Schramm, W. 1947. "Measuring another dimension of newspaper readership." Journalism quarterly 24:293-306.

Schriver, K. 1991. "Plain language through protocol-aided revision." In Plain Language: Principles and practice, ed. E. R. Steinberg. Detroit: Wayne State University Press.

Schriver, K. 1997. Dynamics in document design. New York: Wiley.

Schriver, K. 2000. "Readability formulas in the new millennium: What's the use?" ACM journal of computer documentation 24, no. 3:138-140.

Selzer, Jack. 1981. "Readability is a four-letter word." Journal of business communication 18, no. 4:23-34.

Sherman, A. L. 1893. Analytics of literature: A manual for the objective study of English prose and poetry. Boston: Ginn & Co.

Singer, H. 1975. "The SEER technique: A non-computational procedure for quickly estimating readability levels." Journal of reading behavior 3:255-267.

Smith, E. A. and J. P. Kincaid. 1970. "Derivation and validation of the automated readability index for use with technical materials." Human factors 12:457-464.

Smith, E. A. and R. J. Senter. 1967. Automated readability index. AMRL-TR- 66-22. Wright-Patterson AFB, OH: Aerospace Medical Division.

Spache, G. 1953. "A new readability formula for primary-grade reading materials." Elementary school journal. 53:410-413.

Spilich, G. J., G. T. Vesonder, H. L. Chiesi, and J. F. Voss. 1979. "Text processing of domain-related information for individuals of high and low domain knowledge. Journal of verbal learning and verbal behavior 18: 275-290.