_William Penn_. No Cross, No Crown. London, 1851.

_Plotinus_. The Ethical Treatises, trans. from the Greek by Stephen
Mackenna. London, 1917.

_Plotinus_. The Physical and Psychical Treatises, trans. from the Greek
by Stephen Mackenna. London, 1921.

_J.B. Pratt_. The Religious Consciousness; a Psychological Study. New
York, 1921.

_Richard of St. Victor._ Opera Omnia. Migne, Pat Lat., t. 196.

_W.H.R. Rivers_. Instinct and the Unconscious, Cambridge, 1920.

_Richard Rolle of Hampole_. The Fire of Love and Mending of Life,
Englished by R. Misyn (E.E.T.S. 106).London, 1896.

_Bertrand Russell_. The Analysis of Mind, London, 1921.

_John Ruysbroeck_. The Adornment of the Spiritual Marriage, the Book of
Truth, and the Sparkling Stone, trans. from the Flemish by C.A.
Wynschenk Dom. London, 1916.

--The Book of the XII Béguines, trans. by John Francis. London, 1913.

_R. Semon_. Die Mneme, 2nd ed. Leipzig, 1908.

_Herbert Spencer_. Education: Intellectual, Moral, and Physical London,
1861.