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These started replacing , or at least supplanting , similar gun-based SPAAG systems in the 1960 s , and by the 1990 s had replaced almost all such systems in modern armies .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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