A fragment of a sketch of a string quartet (PBM Aa 219) has survived without tempo markings. A possible connection with the lost Op. 69 in the composer's 1914 List of Compositions III (PBM Na 8) cannot be ruled out. This information is given by Iša Popelka in his Catalogue of Bohuslav Martinů's Autographs, 1997. The existence of the composition is also mentioned in Šafránek's monograph.
Jana Burdová, 2024