A propositional system of modal logic is second-order if it contains quantifiers ∀p and ∃p, which, in the standard interpretation, are construed as ranging over sets of possible worlds (propositions).

Main resource: Discrete mathematics and its applications Teach yourself computer science advises you to read the lecture notes by László Lovász, freely available here as a ps document.

The journal explores symbolic logic and foundations of mathematics relevant to the philosophy and methodology of science; and those facets of the ethics, history and sociology of science which are ...