1. Orion Research Specifications List for Ammonia Electrode Model 95-10; For̊m DS 95-10/1711.Massachusetts, U.S.A.
2. Electronic Instruments Limited, Leaflet No. 8002-2/3.
3. J.W. Ross and J.H. Riseman, Plenary Lecture, International Symposium on Selective Ion-Sensitive Electrodes, Cardiff,1973.