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2. Kuang Zhiquan, Li Jianzeng, Liang Canbin, C Boundary of Taub Plane Symmetric Static bb Vacuum Space-time, Physical Review D, 33, 1533( 1986).

3. Kuang Zhiquan, Liang Canbin, On GKP and BS Structure of C Boundary, Journal of Mathematical Physics, 29,433 (1988).

4. Kuang Zhiquan and Liang Canbin, On Racz and Szabados Structures of c-BBB Boundary, Physical Review D, 46( 10), 4253( 1992).