 Heyting’s paper would indeed be published soon after, in 1930; not in the Mathematische Annalen, as Brouwer by then was no longer on its editorial board, but in the proceedings of the Prussian Academy of Sciences. However, Heyting’s work became known already before its publication. Heyting mentioned it in correspondence with Glivenko in 1928 (see below), Tarski and Łukasiewicz talked about it to Bernays at the Bologna conference in 1928, and Church mentioned it in a letter to Errera in 1929 (Hesseling 2003: 274).