Siljan Ring
... that the Siljan Ring, a very large impact crater in central Sweden, has been the site for two attempts at commercial exploitation of natural gas and oil based on the theory of abiogenic petroleum?
... that the <b id="mwCFE"><a href="./Siljan_Ring" id="mwCFI" rel="mw:WikiLink" title="Siljan Ring">Siljan Ring</a></b>, a very large <a href="./Impact_crater" id="mwCFM" rel="mw:WikiLink" title="Impact crater">impact crater</a> in central Sweden, has been the site for two attempts at commercial exploitation of natural gas and oil based on the theory of <a href="./Abiogenic_petroleum_origin" id="mwCFQ" rel="mw:WikiLink" title="Abiogenic petroleum origin">abiogenic petroleum</a>?