LC autorités [en ligne : 03-05-2005]
Plant Sciences Library, Oxford Forest Info. Service [en ligne : 03-05-2005]
The natural history of Lancashire, Cheshire, and the Peak, in Derbyshire : with an
account of the British, Phœnician, Armenian, Gr. and Rom. antiquities in those parts
/ Charles Leigh, pl. dess. et gr. par Michael Burghers
WBI [en ligne : 03-05-2005]