Source: Per post by Quentin de Givenchy about this soldier and his graffiti at the 18th Battalion Facebook page.
Find-A-Grave
Mercer, Joseph Alfred: Service no. 405768
War Diary of the 18th Battalion CEF
Articles, war diaries, and recognition to the Men of the "Fighting 18th"
Source: Per post by Quentin de Givenchy about this soldier and his graffiti at the 18th Battalion Facebook page.
Find-A-Grave
War Diary of the 18th Battalion CEF 