Rare, huge 16" record for Armed Forces Radio Services (Basic Music Library) from WW-II,

Rare, huge 16" record for Armed Forces Radio Services (Basic Music Library) from WW-II, Volume no.R-39/40 SIDE-1:Church Choir: 5-tracks... SIDE-2: Dorothy Maynor with Frank Black and the NBC Symphony Orchestra:3-tracks. A number of songs, including: Swing Low Sweet Chariot, Sometimes I Feel Like a Motherless Child, Wherefore Dist Thou Leave Me, Eternal Father Strong To Save, Cross of Christ, Onward Christian Soldiers, From Greenland's Icy Mountains and Crown Him With Many Crowns. The total time on the entire record is about 25 minutes. Mint condition. We have no idea as to how many of these exist. Our hunch is that this is quite a scarce historical item.
BACKGROUND: Born Dorothy Leigh Maynor September 3, c. 1910 in Norfolk, Virginia, to Reverend John J. Maynor and Alice Jeffries Maynor; died February 19, 1996, West Chester, Pennsylvania; married Reverend Shelby Rooks, June 24, 1942.
Education: Hampton Institute, B.A., 1933; Westminster Choir School, B.A., 1935; studied singing with Wilfred Klamroth and John Alan Haughton, New York City, beginning 1936.