Ships and marine technology – Graphical symbols for technical documentation – Part 1: General instructions
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 02/01/1998

Ships and marine technology – Graphical symbols for technical documentation – Part 1: Generalities and types of actuation; Text in German and English
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 05/01/2017