Disk in a single "GLASS BASE DISK" paper-covered envelope. [a] & [b] Amadeo Roldan: Ritmicas (from label on paper cover) 16" NORTHERN RADIO COMPANY 33 1/3 RPM (PRESTO NY) Partial labels on disk: one side with two takes (label unreadable), the other side has partial "Son Rumba" and the number "V". center --> edge (recording pattern), 2 tracks on side a, 5 tracks on side b