A post-it accompanies WEEB760-8 (see WEEB2783).

Photographer Photo Geljon (label).
WEEB760-1, -5, -8, -12: entitled de Architekten Cie. (stamp)
WEEB760-9: entitled Hoogstad Weeber Schulze Van Tilburg architekten bna (label)
WEEB760-17: entitled de Architekten Cie. (label)