Submitted on: 11 January 2010.
Revised on: 05 March 2010.
Accepted on: 24 April 2010.
___________________Journal of Geometry---SPRINGER BASEL AG
Submitted on: 25 January 2023.
Revised on: 07 May 2023.
Accepted on: 21 May 2023.
___________________Journal of Geometry---SPRINGER BASEL AG
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Submitted on: 28 October 2022.
Revised on: 04 January 2023.
Accepted on: 25 February 2023.
___________________Journal of Geometry---SPRINGER BASEL AG
Submitted on: 21 April 2024.
Revised on: 05 June 2024.
Accepted on: 30 July 2024.
___________________Journal of Geometry---SPRINGER BASEL AG
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Submitted on: 29 July 1998.
Revised on: 26 September 1998.
Accepted on: 10 November 1998.
___________________Journal of Geometry---SPRINGER BASEL AG
Submitted on: 12 February 2017.
Revised on: 12 May 2017.
Accepted on: 02 July 2017.
___________________Journal of Geometry---SPRINGER BASEL AG
Submitted on: 17 February 2001.
Revised on: 12 March 2001.
Accepted on: 05 May 2001.
___________________Journal of Geometry---SPRINGER BASEL AG