<ref xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mml="http://www.w3.org/1998/Math/MathML" id="R15"><label>15</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Kowalski</surname><given-names>R</given-names></name><name><surname>Wawrzykowski</surname><given-names>J</given-names></name></person-group><article-title>Essential oils analysis in dried materials and granulates obtained from Thymus vulgaris L., Salvia officinalis L., Mentha piperita L. and Chamomilla recutita L</article-title><source>Flavour and Fragrance Journal</source><year>2009</year><volume>24</volume><issue>1</issue><fpage>31</fpage><lpage>35</lpage></element-citation></ref>