Captains may necessarily refer to the following documents:
- French Marine Hydro-graphic Department map No. 5380.
- English Hydro-graphic Office of the Navy map No. 1860.
- French Nautical Instructions, volume V, series C, Africa – West Coast.
- Book of fog lights and signals, series C.
- AFRICA PILOT, Vol II, published by the Hydro-graphic Department, Admiralty, London.