2008GB/T 16900-2008 Rules for the presentation of graphical symbols.General principles
1997GB/T 16900-1997 Rules for the presentation of graphical symbols--General principles
1986GB 7093.1-1986 Graphical symbols represent general rules
GB 7093.1-1986 Graphical symbols represent general rules was changed to GB/T 16900-1997 Rules for the presentation of graphical symbols--General principles.