1. Signaling on Low voltage Electrical Installations in the Frequency Range 3 kHz to 148,5 kHz-Part 1: General Requirements, Frequency Bands and Electromagnetic Disturbances, Standard EN 500651, 1992, 2001;2011 European Committee for Electrotechnical Standardization (CENELEC),2011
2. Power Line Communication Apparatus Used in Low-Voltage Installations-Radio Disturbance Characteristics-Limits and Methods of Measurement-Part 1: Apparatus for In-Home Use;European Committee for Electrotechnical Standardization (CENELEC),2012
3. Low Frequency Circulator/Isolator Uses No Ferrite or Magnet;wenzel;RF Design,1991
4. ACTIVE CIRCULATOR CIRCUITS USING OA, CCII, CFOA AND DVCC
5. Magnet-Less Circulators Based on Spatiotemporal Modulation of Bandstop Filters in a Delta Topology