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His younger sister 's Princess Maria Cristina , was the wife of the future Charles Felix of Sardinia and Queen of Sardinia ; Maria Cristina 's twin Princess Maria Cristina Amelia died in 1783 of smallpox .
 Princess Maria Cristina, Charles Felix of Sardinia, Queen, Sardinia, Maria Cristina, Princess Maria Cristina Amelia
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Princess Maria Cristina, Charles Felix of Sardinia, Queen, Sardinia, Maria Cristina, Princess Maria Cristina Amelia