Symbols and abbreviations used in admiralty. 
 -  The United Kingdom Hydrographic Office.  2005 
 - 75 pages. 
978-0-7077-4048-5
Nautical charts.
M 912.0148 Sy6 2005
                        978-0-7077-4048-5
Nautical charts.
M 912.0148 Sy6 2005