1807
Ukraine 's declaration of independence in 1991 , backed nine-to-one by a referendum in December of that year , effectively dealt a death blow to the Soviet empire and ended more than three centuries of rule from Moscow .
 Soviet, Moscow, Ukraine
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, else, organization, person 
Text: {0} 
Answer:
 Soviet, Moscow, Ukraine