Ivan Nachev

Geological Institute at Bulgarian Academy of Sciences, Sofia 1113

Volume 32 2-4 December 2002

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Volume 30 3-4 February 2001

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Volume 25 5-6 December 1995

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Volume 25 3-4 August 1995