“…according to a person who took part in the meeting.”
“…said a former Democratic Governor of a large Eastern state.”
“…according to local lore.”
“My source for this conversation did not name the person.”
“…according to Hillary’s recollection of their conversation, which she passed on to a friend.”
“…said a member of the Clinton inner circle.”
“…a friend recalled in an interview for this book.”
But not to worry – Klein explains all this at the end of the book in A Note to the Reader.
“…most people were unwilling to be quoted by name, either because they were not authorized to speak on the record or they feared losing access to their powerful friends.
As a result, in order to get a candid and accurate picture of the Clinton-Obama feud, the bulk of the interviews in this book, as in many contemporary political books, had to be conducted on what journalists call “deep background.” In practice, this means that I was able to use the information they provided but could not identify them as a source.”