DIN 13-1
DIN 13-1 ISO general purpose metric screw threads - Part 1: Nominal sizes for coarse pitch threads; nominal diameter from 1 mm to 68 mm
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 11/01/1999
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 11/01/1999