Source: Piero Sraffa: His life, thought and cultural heritage (2000), Ch. 1. Piero Sraffa
Quotes about difficulty
page 6

Speech in the House of Commons (16 May 1820), quoted in George Henry Francis, Opinions and Policy of the Right Honourable Viscount Palmerston, G.C.B., M.P., &c. as Minister, Diplomatist, and Statesman, During More Than Forty Years of Public Life (London: Colburn and Co., 1852), pp. 15-16.
1820s

2009, Cartias in Vertitate (29 June 2009)

The Law of Mind (1892)

“The difficulty in life is the choice.”
Act IV
The Bending of the Bough (1900)

Letter to Husák

"Stockton attacks Thatcher policies", The Times, 9 November 1985, p. 1.
Speech to the Tory Reform Group, 8 November 1985. Often quoted as "selling off the family silver".
1980s

Source: 1920s, Coming of Age in Samoa (1928), p. 1, Opening of introduction
"On Ambiguity" in Rational Meaning and Supplementary Essays (Charlottesville: University of Virginia Press, 1997).

1860s, Our Composite Nationality (1869)

Attributed without citation in "Tigran Petrosian's Best Games" http://www.chessgames.com/perl/chesscollection?cid=1014968 at chessgames.com

On the Hypotheses which lie at the Bases of Geometry (1873)
Source: The Romantic Rebellion (1973), Ch. 13: Degas

Letter to Tom Attlee (1 January 1933), quoted in W. Golant, 'The Emergence of C. R. Attlee as Leader of the Parliamentary Labour Party in 1935', The Historical Journal, Vol. 13, No. 2 (Jun., 1970), p. 323
Deputy Leader of the Opposition

Speech http://hansard.millbanksystems.com/commons/1848/aug/25/employment-of-the-poor-ireland in the House of Commons (25 August 1848).
1840s

Quote in his letter to brother Theo, from Arles, September 1888; as quoted in Vincent van Gogh, edited by Alfred H. Barr; Museum of Modern Art, New York, 1935 https://www.moma.org/documents/moma_catalogue_1996_300061887.pdf, (letter 531) p. 22
1880s, 1888
Source: The Mechanism of Economic Systems (1953), p. 1

Truth of Intercourse.
Virginibus Puerisque and Other Papers (1881)
The Apostles of Sri Ramakrishna

Source: 1980's, Interview with Louwrien Wijers, 1981, p. 189 - in 'Joseph Beuys and the Dalai Lama'

Letter to George Washington (January 1780)

Un contadino che mi dà il suo pezzo di pecorino mi fa un regalo più grande di Giulio Làscari quando m’invita a pranzo. Il guaio è che il pecorino mi dà la nausea; e così non resta che la gratitudine che non si vede e il naso arricciato dal disgusto che si vede fin troppo.
Page 144
Il Gattopardo (1958)

Source: The Natural History of the Soul (1745), Ch. VI Concerning the Sensitive Faculty of Matter

Source: 1960s, Scientific method: optimizing applied research decisions, 1962, p. 1.
Source: Men Under Stress, 1945, p. 38-39 cited in: The Clare Spark Blog (2009) Strategic Regression in “the greatest generation” http://clarespark.com/2009/12/09/strategic-regression-in-the-greatest-generation/ December 9, 2009

1920s, Second State of the Union Address (1924)

1960s, Letter to Ho Chi Minh (1967)

The Hoover Policies (1937)

When describing the sources of his music
New York Times interview (1972)

In, p. 5-6
Gulzarilal Nanda: A Life in the Service of the People

Source: 1890s - 1910s, The Writings of a Savage (1996), p. 214: in a letter to George-Daniel de Monfreid, Marquesas Islands, October 1902

“It is not my experience that life’s difficulties make people more charitable.”
All the Pretty Horses (1992)

The History of Rome - Volume 4: Part 1

Quotations from Gurudev’s teachings, Chinmya Mission Chicago

p, 125
Researches on the effects of bloodletting... (1836)
Herbert N. Casson in: Sheet Metal Workers' International Association (1928) Sheet Metal Workers Journal p. 22
1920s-1940s
Foreword
All Else Is Bondage : Non-Volitional Living (1964)
Source: The practice of social work. (1995), p. 1; On the history of social work

Introduction.
The Psychology of Man's Possible Evolution (1950)
"Evelyn Waugh: Club and Country", p. 101
The Tale Bearers: English and American Writers (1980)

FeelTheBern.org, "Issues" (5 September 2015)
2010s, 2015


L.V. Kantorovich (1996) Descriptive Theory of Sets and Functions. p. 39; As cited in: K. Aardal, George L. Nemhauser, R. Weismantel (2005) Handbooks in Operations Research and Management Science, p. 15-26

5.Paul Samuelson is Human.
Ten Ways to Know Paul A. Samuelson (2006)

Source: The Postman (1985), Section 1, “The Cascades”, Chapter 5 (p. 43)

The People's Rights [1909] (London: Jonathan Cape, 1970), p. 24
Early career years (1898–1929)

Source: Economic Analysis of Law (7th ed., 2007), Ch. 1: The Nature of Economic Reasoning

The Watch Tower (October 15, 1914), p. 287.
Source: Evolution: A Theory in Crisis (1986), p. 77

“Anyone with a good classical education could learn Chinese by himself without difficulty.”
1968 remark, quoted in Japan Quarterly, Vol. XVIII, No. 1 (January-March 1971), p. 107

The Jewish Strategy, Chapter 12 "Christianity"
1990s, The Jewish Strategy (2001)

Source: Lectures on The Industrial Revolution in England (1884), p. 150

Speech at the City of London (17 July 1914), quoted in The Times (18 July 1914), p. 10
Chancellor of the Exchequer

1870s, Self-Made Men (1872)

1920s, Freedom and its Obligations (1924)

CNN Interview (10 December 2003) http://transcripts.cnn.com/TRANSCRIPTS/0312/10/ltm.12.html
Ludwig Wittgenstein: A Memoir, 1958

Source: Education as a Science, 1898, p. 153.

On the creation of the hydrogen bomb, in "Infamy and honor at the Atomic Café : Edward Teller has no regrets about his contentious career" by Gary Stix in Scientific American (October 1999), p. 42-43.

Kenneth Arrow, "Uncertainty and The Welfare Economics of Medical Care", The American Economic Review(1953)
1950s-1960s
Sermon (1899)

Source: The Limits of Evolution, and Other Essays, Illustrating the Metaphysical Theory of Personal Ideaalism (1905), The Harmony of Determinism and Freedom, p.326-7

Cognitive Surplus : Creativity and Generosity in a Connected Age (2010)

Nobel autobiography (1975)

Interview with Heinrich Rohrer at the Nobel Foundation, Stockholm, 9 April, 2008. The interviewer is Adam Smith, Editor-in-Chief of Nobelprize.org.

1920s, The Press Under a Free Government (1925)

Quotations from Gurudev’s teachings, Chinmya Mission Chicago

Speech to the Home Rule Union at the National Liberal Club, London (24 February 1887), quoted in The Times (25 February 1887), p. 4
1880s

Source: Twenty Years at Hull-House (1910), Ch. 8

one week later Cezanne died
Quote in Cezanne's last letter to his son Paul, Aix, 15 October 1906; as quoted in Cézanne, Ambroise Vollard, Dover publications Inc. New York, 1984, p. 112
Quotes of Paul Cezanne, after 1900

"I am a simple Buddhist monk: Dalai Lama" in The Times of India (6 July 2006) http://timesofindia.indiatimes.com/articleshow/1711921.cms.

“To recognize a difficulty is not to solve it.”
Source: Philosophy At The Limit (1990), Chapter 1, The Faces of Silence, p. 9

vassalité
Speech to the Senate (10 February 1912), quoted in David Robin Watson, Georges Clemenceau: A Political Biography (London: Eyre Methuen, 1974), p. 220.

“It is not easy to conceive the difficulties we have had.”
Knox to George Washington on the difficulties of taking to Boston. Reported in David McCullough, 1776 (2005), p. 83.

“Some difficulties meet, full many.
I find them not, nor seek for any.”
J. Roberts, A Sense of the World: How a Blind Man Became History's Greatest Traveler. (New York: HarperCollins Publishers, 2006)

1920s, Ordered Liberty and World Peace (1924)

July, 1918
India's Rebirth

"Mr Macmillan sets out", The Times, 8 January 1958, p. 8
Statement to the press at Heathrow Airport, 7 January 1958. Macmillan was refusing to postpone a Commonwealth tour despite the resignation of the entire Treasury team of ministers.
1920s-1950s

Speech to the annual assembly of the Congregational Union, London (12 May 1931), published in This Torch of Freedom (1935), pp. 86-87.
1931

Quoted in "The Armenians, from Genocide to Resistance: From Genocide to Resistance" - Page 82 - by Gérard Chaliand, Yves Ternon - Social Science – 1983.
The Personality of Jesus (1932)

Source: Mathematical Lectures (1734), p. 388

1960s, Why I Am Opposed to the War in Vietnam (1967)

(A.J. Broomhall. Hudson Taylor and China’s Open Century, Book Five: Refiner’s Fire. London: Hodder and Stoughton and Overseas Missionary Fellowship, 1985, 350).

p, 125
"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)