Data Recording and Monitoring for Analysis of System Response Times. - John P. Penny; Paul J. Ashton; A. L. Wilkinson (Comput. J., 1986)

Instrumenting Systems to Measure Components of Interactive Response Times. - John P. Penny; Paul J. Ashton; D. G. Tripp (Aust. Comput. J., 1988)

Laboratory-style teaching of computer science. - John P. Penny; Paul J. Ashton (SIGCSE, 1990)

A Tool for Visualizing the Execution of Interactions on a Loosely-coupled Distributed System - Paul J. Ashton; John P. Penny (Softw. Pract. Exp., 1995)

Using interaction networks for visualisation of message passing. - Paul J. Ashton (SIGCSE, 1997)