...Sotheby’s will offer the document for sale Thursday, along with two others: the scribbled notes for a speech King planned to deliver in Memphis, Tenn., three days after he was assassinated, and a letter of condolence from former president Lyndon B. Johnson to King’s widow. The auction house put the overall presale estimate for the three documents at US$750,000 to $1.13 million, with the Vietnam speech alone valued at $500,000 to $800,000. ...“I am at the end of my life — I will be 82 shortly — and there are a lot of causes I believe in for which resources...