Lambert, N.M., Hartsough, C.S., Converse, F.L. and Converse, E.K. "APPLE: An Annotated Pupil Information System."Educational Technology, November 1971, pp. 32-36.
2.
Lambert, N.M. and Hartsough, C.S. "APPLE Observation Variables and Their Relation to Reading and Mathematics Achievement." Chapter 1, Volume 3. Beginning Teacher Evaluation Study. Princeton, N.J.: Educational Testing Service, 1975, 1976.
3.
Lambert, N.M., Hartsough, C.S., Caffrey, C. and Urbanski, C.APPLE: Manual for APPLE Observers. Berkeley, Calif .: University of California, 1976 a.
4.
Lambert, N.M., Hartsough, C.S., Caffrey, C. and Urbanski, C.APPLE: Lexicon for APPLE Observations. Berkeley, Calif.: University of California, 1976b.