Jelaskan Production models dari BTR-60

BTR-60s were produced by Gorkovsky Avtomobilny Zavod (GAZ). The BTR-60P was produced between 1960 and 1963. The BTR-60PA entered production in 1963, followed by the BTR-60PA-1 in 1965. Both the BTR-60PA and BTR-60PA-1 were produced until 1966. The BTR-60PAI also entered production in 1965, but was quickly replaced in 1966 by the BTR-60PB, which had a better sighting system for the machine guns. The BTR-60PB remained in production until 1976, when it was superseded by the BTR-70. According to Western estimates, around 25,000 BTR-60s were produced by GAZ. During BTR-80 production, and therefore after BTR-60 production had ended, there was a special production run of 100 BTR-60PBs, some of which have been exported to Iraq.