'In his "Astronomia nova" (1609) Kepler developed a new planetary hypothesis (ch. 16), the "hypothesis vicaria" ... The purpose of this paper is to make a theoretical analysis of Kepler's "hypothesis vicaria", my main concern being to represent his astronomical aims by means of modern theory ... We shall also analyse the "hypothesis nova" which Mercator developed in 1664.'
Archive for history of exact sciences Vol. 41 (1990), p. 53-92