These are three of the best known Sufis. Several of their writings are listed below. To find English language translations of other Sufi writers (and annotations of the books mentioned below) check chapter eight of Paula Skreslet's book "The Literature of Islam'.
Bawa Muhaiyaddeen was a well known 20th century sufi whose fellowship was located close to St. Josephs University in Philadelphia. www.bmf.org The library has many of his writings.