The Workers' Opposition was a faction of the Russian Communist Party that emerged in 1920 as a response to the perceived over-bureaucratisation that was occurring in Soviet Russia. The group argued for increased union control over the economy. In 1921, Alexandra Kollontai wrote "The Workers Opposition" which explained the movement's central theory. The text was outlawed in the Soviet Union later that year.
Alexandra Kollontai, "The Workers Opposition", Pravda, January 25, 1921.(banned in Soviet Russia in March of 1921)