Olah George A., Surya Prakash G.K., Molnár Árpád, Sommer Jean. Superacid chemistry

2nd ed. , extended and updated - Published by John Wiley & Sons, 2009. - 868 p.
The chemistry of superacids, that is, of acid systems stronger than conventional strong mineral Brønsted acids such as sulfuric acid or Lewis acids like aluminum trichloride, has developed in the last two decades into a field of growing interest and importance. It was J. B. Conant who in 1927 gave the name superacids to acids that were capable of protonating certain weak bases such as carbonyl compounds and called attention to acid systems stronger than conventional mineral acids. The realization that Friedel–Crafts reactions are, in general, acid catalyzedwith conjugate Lewis–Brønsted acid systems frequently acting as the de facto catalysts extended the scope of acid catalyzed reactions.General Aspects
Superacid Systems
Carbocations in Superacid Systems
Heterocations in Superacid Systems
Superacid-Catalyzed Reactions