http://reply.papertrans.cn/2/171/17018/17018-31.png
Submitted on: 10 October 2015.
Revised on: 30 January 2016.
Accepted on: 23 March 2016.
___________________Journal of Geometry---SPRINGER BASEL AG
Submitted on: 19 June 2022.
Revised on: 29 July 2022.
Accepted on: 19 August 2022.
___________________Journal of Geometry---SPRINGER BASEL AG
Submitted on: 23 February 1998.
Revised on: 17 May 1998.
Accepted on: 27 June 1998.
___________________Journal of Geometry---SPRINGER BASEL AG
http://reply.papertrans.cn/2/171/17018/17018-35.png
Submitted on: 16 February 2009.
Revised on: 14 May 2009.
Accepted on: 30 June 2009.
___________________Journal of Geometry---SPRINGER BASEL AG