Google Books Ngram Viewer

Graph these comma-separated phrases:
case-insensitive
between and from the corpus with smoothing of .  
Search in Google Books:

1800 - 1917 1918 - 1980 1981 - 1983 1984 - 1999 2000 economic schools of thought English
1800 - 1923 1924 - 1983 1984 - 1989 1990 - 1994 1995 - 2000 schools of economic thought English

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