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MOL (Hungarian Oil Company) – Hungary
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INA (Croatian Oil Company) – Croatia
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CROSCO Drilling Co. – Croatia – Croatia/Syria
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NEMMOCO Co. – Slovenia
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NIS (Serbian Oil Company) – Serbia
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GAZPROM – Astrakhan, Russia
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TESCO Co. – Calgary, Canada
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ROTARY Drilling Co. – Hungary / Syria
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MB Group – Hungary / Oman
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Hungarian Horizon Energy Co./ CED – Hungary / USA
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TOREADOR Hungary Co. – Hungary / USA
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MATRA Blue Star Co.– Hungary
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PETRO Hungaria Co. – Hungary / Great Britain
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EON Gas Storage Co. – Hungary
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Geoinform Ltd. – Hungary
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BJ Rotary Ltd. – Hungary
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TDE Ltd. – Hungary
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OEOC – Iran