The book
*Propositional
and Predicate Calculus: A Model of Argument* by Derek Goldrei goes far
beyond what we cover in MATH0005, but I recommend it if you want to know
about logic in much more depth. You can also take the 3rd year course
MATH0037
Logic.

Chapter 3
of the free online book *Discrete Mathematics: An Open
Introduction* by Oscar Levin
has material on propositional calculus and first order logic, though
it doesn’t use the same framework of well-formed formulas that we do and
the vocabulary they use is slightly different.