Notes
1 See Johannes Goebel, "When he sat down at the piano," in Wolf-Dieter Zimmerman and Ronald Gregor Smith, eds. I knew Dietrich Bonhoeffer: Reminiscences by his Friends (London: Collins. 1966), pp. 124–125.
2 Dietrich Bonhoeffer, Letters and Papers from Prison, DBWE 8, Minneapolis: Fortress Press, 2000, 2010, pp. 393–394.
3 Letters and Papers from Prison, p. 385.