1. Digital system for protection;Cory;CIGRE,1976
2. A digital computer system for EHV substations: analysis and field tests;Phadke;IEEE Trans.,1976
3. Fundamental principles for distance protection;Vitins,1979
4. Micro-computer applications in protection relaying;Petrou,1977
5. Einsatz eines Mikrorechners als Distanzrelais;Koglin,1979