You can also go straight to the source - Look up the speeches and writings of guys like Wolfe Tone, Michael Connolly,

https://en.wikipedia.org/wiki/Cumann_na_mBan

Check out the Republican women's paramilitary, too.

I read a book a bit ago called "Bandit Country" about the IRA units in South Armagh. Went a lot in to the differing character of IRA units vs the Brit's assorted gangs of neo-nazis and assassins, talked about tactics and relative impact, had a lot to say about teh importance of never saying a damn thing if you want your insurgent cell to survive.

"War and an Irish Town"