1. Stern, J.R., and Dyott, R.B.: ‘Launching into single-mode optical fibre waveguide’, Trunk telecommunications by guided waves, 1970),71, p. 191–196 IEE Conf. Publ.
2. Krumpholz, O.: ‘Trunk telecommunications by guided waves’, Mode propagation in fibres: discrepancies between theory and experiment, 1970),71, p. 56–61 IEE Conf. Publ.