Nyanaponika Thera (2005). “The Heart of Buddhist Meditation: Satipaṭṭhāna : a Handbook of Mental Training Based on the Buddha's Way of Mindfulness, with an Anthology of Relevant Texts Translated from the Pali and Sanskrit”, p.25, Buddhist Publication Society
"The Impact of Labour, 1920-1924: The Beginnings of Modern British Politics" by Maurice Cowling, Cambridge: Cambridge University Press, (p. 147), 1971.