Simple portfolio rebalancing
The following books are great resources for learning about passive investing:
The Four Pillars Of Investing, William J. Bernstein
A Wealth Of Common Sense, Ben Carlson
A Random Walk Down Wall Street, Burton Malkiel
Stocks For The Long Run, Jeremy Siegel
The Little Book Of Common Sense Investing, John C. Bogle
The Clash Of The Cultures: Investment Vs. Speculation, John C. Bogle
Fooled by Randomness: The Hidden Role of Chance in Life and in the Markets, Nassim Nicholas Taleb
The Intelligent Investor, Benjamin Graham
Where are the Customers’ Yachts?, Fred Schwed
Rich Dad Poor Dad, Robert Kiyosaki
The Millionaire Next Door, Thomas J. Stanley