Question: The CASA 2. 111 was a medium bomber derived from what German aircraft that was designed by Siegfried and Walter Gunter at Heinkel Flugzeugwerke in 1934?
Sentence (from "Heinkel He 111"): The Heinkel He 111 was a German aircraft designed by Siegfried and Walter Günter at Heinkel Flugzeugwerke in 1934.
Relevant evidence: Yes