APA (7 वां संस्करण) प्रशस्ति पत्र

Mark, K. (1993). Valved Friends: For two trumpets and band / Koos Mark (Full score, condensed score.). Molenaar.

शिकागो शैली (17वां संस्करण) प्रशस्ति पत्र

Mark, Koos. Valved Friends: For Two Trumpets and Band / Koos Mark. Full score, condensed score. Wormerveer, Holland: Molenaar, 1993.

एमएलए (8वां संस्करण) प्रशस्ति पत्र

Mark, Koos. Valved Friends: For Two Trumpets and Band / Koos Mark. Full score, condensed score. Molenaar, 1993.