I now realize that several pieces (6 actually) scattered on the Balbastre main page should have been filed under the "Livre contenant des Pieces... (1749)", section: ORGAN solo.
Since that book contains 40 pieces, and I do not yet know how to correct the wrong filing without possible damage, I'm asking if someone more clever could be kind enough to do it.
Here are the pieces misfiled to this day:
• Concert de flûte et de voix humaine is no 13.
• Concerto is no 1 and 2 (Prelude, Allegro).
• 'Fugue in d minor' should remain there; but the Duo (1749) is no 9.
• Gavotte is no 3.
• Tapage is no 40.
• Trio à trois mains is no 38.
all should be filed under "Livre contenant des Pieces... (1749)", section ORGAN solo, where they belong.