7897
It was learned that the " Duan & Duan Law Firm " in Shanghai was founded in 1993 by Qihua Duan , a lawyer who returned to China with a US Master 's degree .
 the " Duan & Duan Law Firm ", Shanghai, 1993, Qihua Duan, China, US, Master 's degree
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: date, organization, person, geographical social political, national religious political, facility, cardinal, location, work of art, law, event, product, ordinal, percent, time, quantity, money, language 
Text: {0} 
Answer:
 the " Duan & Duan Law Firm ", Shanghai, 1993, Qihua Duan, China, US, Master 's degree