Bertz has issued three publications on Whitman: see especially his _Der Yankee-Heiland_, 1906, and _Whitman-Mysterien_, 1907.

The arguments of Rivers are concisely stated in a pamphlet entitled _Walt Whitman's Anomaly_ (London: George Allen, 1913).

Both Bertz and Rivers emphasize the feminine traits in Whitman.

An interesting independent picture of Whitman, at about the date of the letter to Symonds, accompanied by the author's excellent original photographs, is furnished by Dr.John Johnston, _A Visit to Walt Whitman_, 1898.

It may be added that, probably, both the extent and the significance of the feminine traits in Whitman have been overestimated by some writers.