'Trigonometrical polynomials', published as 'The zeros of trigonometrical polynomials', Mathematika, 19, 1972, 88-90, with the footnote:
'This note has been prepared for publication by Professor H. Halberstam from a draft manuscript sent to him in 1967 by the late Professor Davenport in the course of a correspondence on the large sieve inequality; specifically, Halberstam had asked Davenport whether the inequality might not have some applications in the theory of trigonometrical polynomials and the note came in reply to this query.'
3pp. ms. note by Davenport; letter from Halberstam returning it to him, March 1968.
Letter to Mrs. Davenport from C. A. Rogers, March 1972, enclosing photocopies of her husband's original draft and the proposed paper Halberstam had prepared from it.