Sheet number: 51b NW3, edition 4B + 51b NW4, edition 1A (parts of). Detail & grid black; German trenches red. "N.B. Co-ordinates are not to be taken off these sheets. Every dug-out is not necessarily shown." Reference to OPs, dug-outs, TMs etc. All printed on [XVII Corps] duplicator., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC17; envelope_number: 491