Hi; so, to discuss causes and effects of Italian Fascism is quite a task. I think it would be a good idea to focus on a topic that allows you to draw from your general knowledge of the period and develop a clear - more in depth - argument.

With this in mind I would suggest that you add to your sources Paxton's Anatomy of Fascism that gives both a good overview of Fascism and some interesting starting points; for example the pattern linking fascist movements and agrarian workers throughout europe - unfortunately I believe that most of the literature (for example A. Roveri's work on Ferrara's fascism - La nascita del fascismo a Ferrara and other works) discussing agrarian fascism (in Italy) is not translated.

Another interesting point is that of "failed fascisms" as authoritarian regimes that were able to control and smother the radical tendencies, assuming a conservative form; this may be interesting if you have some previous knowledge of countries such as Romania or Hungary, and again is discussed by Paxton.

A common point of Italian literature on the subject is the continuity vs breach, describing the relation between Fascism and the previous Liberal State - unfortunately here again most of the work is in Italian (for example R. Vivarelli's Il fallimento del liberalismo) and I am not aware of a good English source on the subject - not one that I have read.

If you want to look into the origins of fascism, I would nonetheless consider at least one of the various overviews on the Risorgimento process and post-unitary Italy - Mack-Smith is still a good starting point. Maybe something on Mazzini's "religion of the Nation", without pushing the analogy too far.

Speaking of that, another interesting work on the development of Fascism is that of E. Gentile on "fascist ideology" - here you can find a more (perhaps too much for your purpose) in depth approach, and also something that is translated in English. As this deals with the idea of the "action squad" as a heritage of the WW1 assault squads, it might be linked with the "trench values" and the transformations of interventionism in the post war society.

If you are more interested in the established Regime, De Felice would be the best source - if you could read Italian. Anyways, and with the observation that a discussion of this period becomes somehow more problematic due to the evolving nature of the political system, it might be interesting to address the perception of Fascism in foreign countries, especially in relation to the expat phenomenon and the development of anti-fascism.

The economical policies of the Regime might be interesting - depending on your curriculum - but also quite challenging. I would really focus on the development of fascism, as many of the mature Regime's features are influenced by that "unwilling" syncretism with the Crown and the Church, that are difficult to discuss without a good understanding of those too. This point is briefly discussed by S. G. Payne in his overview.

Unfortunately I can't suggest as many English sources as Italian ones, so I don't know how helpful this will be. Let me know if I can help with something else, though. And I'd really include Paxton's book - no matter what you choose.