National Cathedral
Washington
DC
This is what I found at the Stanford Inventory of MLK works. When I got this speech it was dated 3/30/68, but it is really 3/31/68.
3/31/68
King, Martin Luther, Jr. "Remaining Awake Through a Great Revolution, Sermon delivered at the National Cathedral." 3/31/68. Washington, D.C. (At) 47 min. (1 sound cassette: analog.) MLKJP-GAMK: T-60. 680331-000.
3/31/68
King, Martin Luther, Jr. "Remaining Awake Through a Great Revolution, Sermon delivered at the National Cathedral." 3/31/68. Washington, D.C. (TD) 11 pp. CSKC: Sermon box, folder 195. 680331-002.