International Federation for Information Processing Technical Committee., IFIP TC6 International Workshop on Protocol Test Systems, Kroon, J., Heijink, R. J., & Brinksma, E. (1992). Protocol test systems IV: Proceedings of the IFIP TC6 Fourth International Workshop on Protocol Test Systems, organized by PTT Research, Leidschendam, The Netherlands, 15-17 October, 1991. Amsterdam: North-Holland.

International Federation for Information Processing Technical Committee., IFIP TC6 International Workshop on Protocol Test Systems, Jan Kroon, Rudolf J. Heijink, and Ed Brinksma. Protocol Test Systems IV: Proceedings of the IFIP TC6 Fourth International Workshop On Protocol Test Systems, Organized By PTT Research, Leidschendam, The Netherlands, 15-17 October, 1991. Amsterdam: North-Holland, 1992.

International Federation for Information Processing Technical Committee., et al. Protocol Test Systems IV: Proceedings of the IFIP TC6 Fourth International Workshop On Protocol Test Systems, Organized By PTT Research, Leidschendam, The Netherlands, 15-17 October, 1991. Amsterdam: North-Holland, 1992.