Low-frequency cables and wires with p.v.c. insulation and p.v.c. Sheath - Part 4: Distribution wires with solid conductors, p.v.c. insulated, in pairs, triples, quads and quintuples IEC 189-4 /  
 IEC 189-4 
ISO, IEC. 
 - 2nd edition. 
 - Geneva :   ISO :   IEC,   1980. 
 - 19 stron ;   30 cm.