Mark, K. (1993). Valved Friends: For two trumpets and band / Koos Mark (Full score, condensed score.). Molenaar.
Chicago-Zitierstil (17. Ausg.)Mark, Koos. Valved Friends: For Two Trumpets and Band / Koos Mark. Full score, condensed score. Wormerveer, Holland: Molenaar, 1993.
MLA-Zitierstil (8. Ausg.)Mark, Koos. Valved Friends: For Two Trumpets and Band / Koos Mark. Full score, condensed score. Molenaar, 1993.
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