References
- Annett , J. 1963 . Personal communication
- Crowder , N. A. and Martin , G. C. 1962 . Trigonometry: A First Course. , London : E.U.P. (TutorText Series) .
- Wallis , D. 1964 . Interim Report on a Second Collingwood Study of Programmed Instruction , London : Ministry of Defence (Navy Department) . Note SP/DW/1/64
- Wallis , D. and Wicks , R. P. 1962 . A Comparative Study of Teaching Machines and Classroom Instruction in a Naval Training Establishment , London : Ministry of Defence (Navy Department) . Report SP 2/62