International Telecommunication Union (ITU),
Directives concerning the protection of telecommunication lines against harmful effects from electric power and electrified railway lines: 1-74, ISBN 978-92-61-12501-1
American National Standards Institute (ANSI), Association for the Advancement of Medical Instrumentation (AAMI),
ANSl/AAMI PC69:2007: 1-81, ISBN 978-1-57020-295-7