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In his spare time he studied botany , and through a mutual friend met German botanist Albrecht Wilhelm Roth ( 1757 – 1834 ) .
 Albrecht Wilhelm Roth
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Albrecht Wilhelm Roth