De Duitse negatieven (en: The German negatives) is an online collection where you can search for Belgian artistic heritage that was photographed in 1917 and 1918. The images are linked to the Royal Institute of Art’s database, BALaT, containing more than 700 000 downloadable photos.
link: De Duitse Negatieven

CEGESOMA, Centre for Historical Research and Documentation on War and Society, is the Belgian centre of excellence for the history of 20th century conflicts. It carries out research, organises public events and holds document collections. Pallas allows the reader to search the archives, the library and the audiovisual collections of Cegesoma with a few mouse clicks.
link: Cegesoma Archief: Pallas