Submitted on: 21 March 2011.
Revised on: 26 April 2011.
Accepted on: 18 May 2011.
Proceedings of the Estonian Academy of Sciences
Submitted on: 08 June 2012.
Revised on: 06 July 2012.
Accepted on: 26 July 2012.
Proceedings of the Estonian Academy of Sciences
Submitted on: 19 October 2010.
Revised on: 11 November 2010.
Accepted on: 25 November 2010.
Proceedings of the Estonian Academy of Sciences
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Submitted on: 04 June 2008.
Revised on: 15 July 2008.
Accepted on: 24 July 2008.
Proceedings of the Estonian Academy of Sciences
Submitted on: 23 September 2016.
Revised on: 03 October 2016.
Accepted on: 09 October 2016.
Proceedings of the Estonian Academy of Sciences
http://reply.papertrans.cn/3/253/25279/25279-17.png
Submitted on: 03 November 2012.
Revised on: 22 November 2012.
Accepted on: 14 December 2012.
Proceedings of the Estonian Academy of Sciences
Submitted on: 30 September 2002.
Revised on: 20 October 2002.
Accepted on: 13 November 2002.
Proceedings of the Estonian Academy of Sciences
Submitted on: 20 April 2001.
Revised on: 04 May 2001.
Accepted on: 26 May 2001.
Proceedings of the Estonian Academy of Sciences