Triste Nº.3 composed by Julián Aguirre and arranged by José Luis Merlin for flute (violín) and guitar. There is also a violoncello and guitar version available.

WATCH VIDEO José Luis Merlin(guitar) and Etienne Plasman (flute) HERE:

https://www.youtube.com/watch?v=ADRqfpqx5Co&index=2&t=0s&list=PL25kC1BTRBxsNXe3WvoFpkISfKgaHtBky&ab_channel=EvgeniyaKirilyuk

WATCH VIDEO José Luis Merlin(guitar) and Ekaterina Chernova (cello) HERE:

https://www.youtube.com/watch?v=pKXUa7XAggA&ab_channel=EvgeniyaKirilyuk