1976   Using Language Laboratory for Teaching Listening Comprehension: Techniques and Material Preparation. Singapore: Regional English Language Centre.

1979   Six Factors Affecting Thai Students’ Achievement in Learning English as a Foreign Language. Scotland: Faculty of Applied Linguistics, University of Edinburgh.

1985   The Effects of Item Weights on English Reading Comprehension Tests with Different Schemata. Bangkok: Faculty of Education, Chulalongkorn University.