<ref xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mml="http://www.w3.org/1998/Math/MathML" id="R5"><label>5</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Thompson</surname><given-names>JD</given-names></name><name><surname>Chalchat</surname><given-names>JC</given-names></name><name><surname>Michet</surname><given-names>A</given-names></name><name><surname>Linhart</surname><given-names>YB</given-names></name><name><surname>Ehlers</surname><given-names>B</given-names></name></person-group><article-title>Qualitative and quantitative variation in monoterpene co-occurrence and composition in the essential oil of Thymus vulgaris chemotypes</article-title><source>Journal of Chemical Ecology</source><year>2003</year><volume>29</volume><issue>4</issue><fpage>859</fpage><lpage>880</lpage><pub-id pub-id-type="pmid">12775148</pub-id></element-citation></ref>