Consists of two unsigned letters addressed to Hartlib. Probably written by Cressy Dymock. Cf. Halkett & Laing (2nd ed.); BM.
Reproduction of original in Harvard University Libraries.
Microfilm. Ann Arbor, Mich. : University Microfilms, 1964. 1 microfilm reel ; 35 mm. (Early English books, 1641-1700 ; 141:13)