See Obama's here. Biden's here.
Obama's disclosure has interesting information about his book sales. In 2009, he contracted to write a young adult version of his book "Dreams From My Father," in which he gets a $500,000 advance against sales. His royalties will be 15% of the US sales price for hardcover and 7.5% to 10% for paperback sales and 10% for mass market sales. What, no ebook sales?