1. A simple and precise borehole extensometer
2. Cole K. W. “Discussion ” Proceedings Symposium on Field Instrumentation in Geotechnical Engineering Butterworths Ltd. London 1973 pp. 623–232.
3. Collet H. B. “Field Vane Tests in Clay Deposits near Rio de Janeiro ” (in Portuguese) thesis presented to Federal University of Rio de Janeiro at Brazil in 1978 in partial fulfillment of the requirements for the degree of Master of Science (in Portuguese).