[Advertising studies] 6x: (1) "Elken dag 1 Bols".

Original design in gouache on cardboard, signed "O. Jonker" bottom left, 68 x 48 cm. (fold in left top corner).

(2) "Hille's Koek en beschuit Zaandam". Original design in gouache, signed "B. Schulte" top right, 32.5 x 50 cm.; (3) "Pepsodent Tandpasta. De eenige met irium". Original design in gouache, signed "Th.W. Challa 27 28 Jan 2 3 4 Febr. '38" top right, 37.5 x 65.5 cm. Foxing and with smaller defects; (4) "Palma's West-Indische Chocolade 25 ct. per ons". Original design in gouache, unclearly signed top right, 32.5 x 50 cm. And with 2 similar works on King Pepermunt (by Challa) and on Appelmoes (by C. Streng). (total 6)