Madalpingelised elektripaigaldised. Osa 5-56, Elektriseadmete valik ja paigaldamine. Turvasüsteemid = Low-voltage electrical installations. Part 5-56, Selection and erection of electrical equipment. Safety services (IEC 60364-5-56:2009)2011 https://www.ester.ee/record=b2716011*est