November-December 1934. 8 letters.
19 November 1934 (the title of Turing's
dissertation was 'On the Gaussian Error Function’ and it is available online
from the Turing Digital Archive),
27
November 1934, 17 December 1934.
Note that file comprises correspondence with the Provost of
King’s College regarding Turing’s dissertation, not with Turing himself.