Let me explain my math background first. I recently finished "how to prove it" by velleman at home. That's it.
I stumbled upon "Introduction to Mathematical Logic, Sixth Edition" by Elliott Mendelson as a prerequisite for ordinal logic that alan turing helped pioneer.
Many amazon reviews on the fifth and sixth editions say it's not for self learners who are not familiar with logic already.
I'm starting to consider "An Introduction to Mathematical Logic" by Richard E. Hodel.
Can anyone give a good recommendation for my self-study material?