*[http://www.flowersofindia.net/catalog/slides/Sow%20Thistle.html Flowers of India]
*[http://botanical.com/botanical/mgmh/s/sowthi71.html#com Grieve's herbal]
*[httphttps://wwwnpgsweb.ars-grin.gov/cgi-bingringlobal/npgstaxon/html/tax_search.pltaxonomydetail?Sonchus%20oleraceus id=34939 GRIN]
*[http://www.ipni.org/ipni/simplePlantNameSearch.do?find_wholeName=Sonchus%20oleraceus&output_format=normal&query_type=by_query&back_page=query_ipni.html IPNI]
*[http://mansfeld.ipk-gatersleben.de/apex/f?p=185:46:10548481770984::NO::module,mf_use,source,akzanz,rehm,akzname,taxid:mf,,botnam,0,,Sonchus%20oleraceus,31994 Mansfeld]