Giles Constable  <br />Saint Bruno of Cologne and solitude,  in: Marsha Dutton, Daniel M. LaCorte & Paul Lockey (eds.), Truth as gift: studies in medieval Cistercian history in honor of John R. Sommerfeldt, Kalamazoo (Mich.), 2004, 27-41 (= Cistercian studies series, 204)  <br />[Constable 2004]