bonsoir,
I spotted these duets, probably taken here:
Bandonéon - ony Muréna & Marcel Azzola & Jean Bingler - Histoire d'un tango (Bandonéon A + B) (Orchestration)
Tucan (Bandonéons A + B) (Tango)
Jacques Cahan - Aquarium (Bandonéons A+B, pno, sax alt.mib) (Tango)
Rog Virèle & Paul Borrelly - Café Bresilien (Creation Joseph Colombo) (Bandoneon A+B) (Typical Tango)
Volver (Arreglo basado en el Duo de Troilo-Piazzolla) (Adaptación Hugo Satorre) (Duo de Bandonéons) (Tango)
René Denoncin & Tony Muréna & Roger Desbois - Tango de l'arc en ciel (Bandonéon A + B) (Orchestration)
we take bandonéon A for the violin, and bandonéon B for the bandonéon.. adapt to what you find...
if you have piano music, you give the right hand to one instrument and the left to the other... you try, you find, or you don't, but it often works... good luck!