Source 3 states "Martha Bradbury arrived with his wife [sic], to serve 4 years."
(1) Walter Lee Sheppard, Passengers and Ships Prior to 1684: Penn's Colony: Genealogical and Historical Materials Relating to the Settlement of Pennsylvania, Vol. I, (1970; reprint, Baltimore: Genealogical Publishing Co., 1985), 65 n 128.
(2) "The Registers Office of All Persons Residing or Inhabiting within the County of Berks, As Well Freemen & Servants & the Time of the Said Servants Freedome & Wages, 1681-1689," Historical Society of Pennsylvania, Philadelphia, Pennsylvania, Microfilm 20452 Item 2, Family History Library, Salt Lake City, Utah.
(3) "A Partial List of the Families Who Resided in Bucks County, Pennsylvania, Prior to 1687, with the Date of their Arrival," Pennsylvania Magazine of History and Biography, Vol. 9 (1886): 223-233.