Concise and good book on doing mathematical proofs. Also: free
There is a Providence that protects idiots, drunkards, children and the United States of America - Otto von Bismark
formal::
P(x) = x is a Providence; S(x,y) = x protects y; R = union of the four sets: idiots, drunkards, children, USA
formal::
E(x) = Event happens to x, F(x) = x is funny