I read books by Malkiel, Ellis, Swedroe & Bob Clyatt & came up with my own mix of large cap, small cap, international, emerging, reits, mid term treasuries & corp bonds, short term corp bonds & TIPS. All mutual fund or ETFs.
One of Swedroe's books goes into a good discussion on setting your bond allocation - based on number of years of safe expenses, ability to handle a 50% equity down turn etc. I can't remember the name though - it may the the "Best investment policy" or something like that. He has the worst names for his books
All the best.