Zhou Qing-Yong, Wei Zi-Qing, Yan Lin-Li, Sun Peng-Fei, Liu Si-Wei, Feng Lai-Ping, Jiang Kun, Wang Yi-Di, Zhu Yong-Xing, Liu Xiao-Gang, Ming Feng, Zhang Fen, He Zhen-Ni. Space/ground based pulsar timescale for comprehensive PNT systemJ. Acta Physica Sinica, 2021, 70(13): 139701. DOI: 10.7498/aps.70.20210288