Concert: Cercle Artístic de Barcelona On December 10, 2016, a concert was held at the Reial Cercle Artístic in Barcelona with the participation of Oyuna Baturova Grup, Ralph Zurmühle, violinist César Mateos and Dueto Amalgama with Montserrat Oliveras on piano and soprano Cristina Ruiz. Oyuna Baturova GrupRalph ZurmühleCésar MateosM. Oliveras and C. Ruiz