Compare and contrasting, Stalinism and Trotskyism

[Reznov]

Ok, so there have been numerous discussions separating the polices and such of these two.

However, are there any good works that really establish the difference between Stalinism and Trotskyism?

Mainly, from where each begins, and then starts to go wise.

[Black Sheep]

read on:
the permanent revolution (a la trotsky)
stage theory
popular vs united front