Peel 2936 : Clark, George Harold (1852-1935?) [détails]; Fletcher, James (1852-1908) [détails]; Criddle, Norman (1875-1933) (illustrator) [détails]. Farm weeds of Canada. Ottawa : Department of Agriculture, Branch of the Seed Commissioner, 1906. .
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Peel 2936 : Clark, George Harold (1852-1935?) [détails]; Fletcher, James (1852-1908) [détails]; Criddle, Norman (1875-1933) (illustrator) [détails]. Farm weeds of Canada. Ottawa : Department of Agriculture, Branch of the Seed Commissioner, 1906. .