Petar Gočev

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Volume 25 2 April 1995

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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Volume 23 3 June 1993

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

Volume 22 6 December 1992

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

Volume 22 3 June 1992