Pierre Vellones Documentary
Here is a fascinating 1993 documentary on composer Pierre Vellones (1889-1939), one of Maurice Martenot's early collaborators, and among the first to compose works for the ondes Martenot.
Of particular interest to me was the section beginning at 16:00, which features an interview with Ginette Martenot, as well as excerpts from the following works by Velonnes:
"Fantaisie" for ondes and piano (1930 - unpublished), performed by Jean-Philippe Dartois and Sophie Cieren; the second known work for ondes according to Laurendeau.
"Vitamines" for ondes and ensemble (1935 - ed. Salabert), composed for ondes and saxophone quartet (recorded at the time for Columbia, along with "Split")
"Karakoram" for 7 ondes Martenot, piano and eastern ensemble (1935 - unpublished
"Fête Fantastique" (1937 - unpublished?) for three ondes and large exotic ensemble
"Une aveture de Babar" (1936 - ed. Lemoine, available as a recording)
The Fantaisie and Fête Fantastique are of considerable historical importance.