Kuhn refers to the book 
 
Ludwik Fleck: Entstehung und Entwicklung einer wissenschaftlichen Tatsache, 1935/reprint
1980 (Frankfurt: Suhrkamp)
 
In the introduction of  his "The Structure of Scientific Revolutions" Kuhn quotes Fleck. 
 
However, a comparison between both works shows how much of Kuhn was already prethought in
Fleck.
 
Dieter Boegenhold