Watch List notes:

BULGARIA: 20 Leva (1988) in silver (0,500) commemorating the Soviet-Bulgarian Space Flight. National arms above denomination, date at left on obverse. Astronauts on reverse. Inside slab by NGC "PF 68 ULTRA CAMEO / JOINT SPACE FLIGHT". Cert number: 6389132-092. (KM 174) & (Nikolov 224).