1. Frequency Analysis of Vowels Produced in a Helium-Rich Atmosphere;Beil;J. Acoust. Soc. Amer.,1962
2. Multiple-Choice Intelligibility Tests, Forms A and B;Black;J. Speech Hearing Disorders,1963
3. Spectrographic Analysis of Diver's Speech During Decompression;Brubaker;J. Acoust. Soc. Amer.,1968
4. Discrimination Test Word Difficulty;Campbell;J. Speech Hearing Res.,1965
5. Clarke, F. R. (1965). Technique for Evaluation of Speech Systems, Stanford Research Institute's Final Report 5090, U.S. Army Electronics Laboratory, Contract DA 28–043 AMC-00227 (E), August, 1965, 1–65.