Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Propaganda in the Soviet Union:

"

As Stalin drew power to himself, Trotsky was pictured in an anti-personality cult. It began with the assertion that he had not joined the Bolshevists until late, after the planning of the October Revolution was done.[1]