Politico | The New Yorker
Ryan Lizza's story about President Barack Obama's struggle to create a "post-partisan" presidency is based on official memos and documents, including Obama's handwritten notes. He tells Politico's Dylan Byers and Jennifer Epstein why:

“I spoke with dozens of White House officials over the last few years, and what I learned is people don’t have very reliable memories,” Lizza said. “They contradict themselves. You look at the paper trail, and you realize what they told you isn’t true. So I decided to rely almost exclusively on primary source material.”

Earlier: Jodi Kantor doesn’t mind not getting access to Obamas for her book, but Erik Wemple doesn't buy it (Poynter)