1949年加盖 "限甘宁青区贴用", 紫色人手加盖于国内平信单位票, 橙黄色及红色人手盖于国内航空单位票, 全套共两枚, 新票无背胶. 均具J.R. Hughes 签署, 他是这项邮票的专家. 陈目S68-69.China Silver Yuan and Unit Stamps Kansu-Ninghsia-Tsinghai: 1949 handstamped overprint in violet on the domestic unit stamp in orange and in red on domestic airmail unit stamp in bright blue-green, both unused without gum as issued. Both have been signed by J.R. Hughes, the foremost specialist of these issues. Chan S68-69. Photo