How to account for pensions

Hi everyone, I've been a diehard Boglehead since long before I learned that this community exists. I'm 35 years old and am fortunate to have worked in a union company since the age of 17. (the same year I began contributing to my first Roth IRA and matched 401k plan!) Anyway, I'm fortunate enough to have not just 1 but technically 4 pensions. A cash balance pension and a normal pension from an old company, and a cash balance pension and normal pension from my current company. I know this is a bit of a niche topic these days, but I was wondering if anyone could point me to resources about how to account for pensions in your financial planning. I read briefly that they can sort of take the place of bonds in an investment portfolio but I am not sure how exactly to factor them in. Specifically looking for things that approach them from the Boglehead perspective. Thanks in advance!