contrabassist with Astor Piazzolla's [artist:7995db10-850a-4219-9b27-191f363d3ccb|Octeto Buenos Aires] Juan Antonio Vasallo: https://todotango.com/creadores/ficha/2097/Juan-Vasallo but discogs has a different middle name, Juan José Vasallo: https://www.discogs.com/artist/3326119 (and there is no "Juan Antonio Vasallo" listed at discogs)