1979: Vietnam forces Khmer Rouge retreat 1979: Vietnam forces Khmer Rouge retreat 1979: Vietnam forces Khmer Rouge retreat 1979: Vietnam forces Khmer Rouge retreat 1979: Vietnam forces Khmer Rouge retreat 1979: Vietnam forces Khmer Rouge retreat 1979: Vietnam forces Khmer Rouge retreat 1979: Vietnam forces Khmer Rouge retreat 1979: Vietnam forces Khmer Rouge retreat overthrew