"William Butler" in John Aubrey, Brief Lives (Andrew Clark, ed., Brief Lives, chiefly of contemporaries, set down by John Aubrey between the years 1669 and 1696 [2 voll. Oxonii: Clarendon Press, 1898] vol. 1 pp. 138-143)
H. R. Trevor-Roper; Blair Worden, ed., Europe's physician: the various life of Sir Theodore de Mayerne (Novo Portu: Yale University Press, 2006 Exemplar mutuabilis) pp. 101-110