Days with Walt Whitman : with some notes on his life and work - Carpenter, Edward, 1844-1929 (George Allen, 1906)
"The notes made on the occasions of ... visits [to Whitman in 1877 and 1884] were ... published in the Progressive review (February and April 1897) in the same form as they now stand. The other papers ... with one exception, have not been published before."–Pref.