An experimental dissertation on the rhus vernix, rhus radicans and rhus glabrum commonly known in Pennsylvania by the names of poison-ash, poison-vine and common sumach - Horsfield, Thomas 1773-1859 (Printed by Charles Cist, no. 104, North Second Street, 1798)
"An inaugural dissertation for the degree of Doctor of Medicine ... University of Pennsylvania, on the 22d day of May, 1798."--p. [iii]. - Austin, R.B. Early Amer. medical imprints, 951. - Evans, 33905