ISO 81714-1:2010

Design of graphical symbols for use in the technical documentation of products - Part 1: Basic rules

IEC 81714-2:2006

Design of graphical symbols for use in the technical documentation of products - Part 2: Specification for graphical symbols in a computer sensible form, including graphical symbols for a reference library, and requirements for their interchange

IEC 81714-3:2004

Design of graphical symbols for use in the technical documentation of products - Part 3: Classification of connect nodes, networks and their encoding