Anyone interested in learning more about how tax avoidance and havens work as well as large company 'best-practices' might be interested in reading Treasure Islands by Nicholas Shaxson.
Book site: http://treasureislands.org
Amazon: http://www.amazon.co.uk/Treasure-Islands-Havens-Stole-World/...
Disclaimer: There's a referral code in the Amazon link for my college's library