太过坚持，也有问题
117 男孩的母亲醉心于音乐和美术：凡·高生平的细节来自几个主要来源，包括写给凡·高的翻译信件。在凡·高博物馆、惠更斯荷兰历史研究所和文森特·凡·高信件网站（vangoghletters.org）上共计900多封信（也就是每一封幸存的信件）。如果没有另一个令人难以置信的参考来源，我不会知道应该读哪封信：史蒂芬·奈菲和格雷戈里·怀特·史密斯的著作《凡·高：生活》Van Gogh: The Life (New York: Random House, 2011)奈菲和史密斯采取了非同寻常的举措，在vangoghbiography y.com/notes.php上创建了一个可搜索的资源数据库。这非常有帮助。另外两个有帮助的书面资料来源是：N. Denekamp et al., The Vincent van Gogh Atlas (New Haven, CT: Yale University Press and the Van Gogh Museum, 2016); and J. Hulsker, The Complete Van Gogh (New York: Harrison House/H. N. Abrams, 1984).最后，再为大家附上两个展览：芝加哥艺术学院的《凡·高的卧室》“Van Gogh’s Bedrooms” (2016)，以及俄罗斯圣彼得堡隐士博物馆的印象派和后印象派藏品。
118 “他其实谁也没记住”：Naifeh and Smith, Van Gogh: The Life.
118 “绝对一个也没见过”：来自凡·高写给弟弟西奥的信，1884年6月。
118—119 “停止随心所欲”；“更快乐、更冷静”；“赶紧继续”：Naifeh and Smith, Van Gogh: The Life.
119 “我就必须坐起来”：Van Gogh letter to brother Theo, September 1877.
119 “地狱”：Émile Zola, Germinal, trans. R. N. MacKenzie (Indianapolis: Hackett Publishing, 2011).
120 “笼子的栏杆”：来自凡·高写给弟弟西奥的信，1880年6月。
120 “我正一边画画一边给你写信”：来自凡·高写给弟弟西奥的信，1880年8月。
120 《基础绘画指南》：Naifeh and Smith, Van Gogh: The Life.
121 “你不是艺术家”；“你开始得太晚了”：Van Gogh letter to brother Theo, March 1882 (trans. Johanna van Gogh-Bonger).
121 “他有了一个巨大的发现”：Naifeh and Smith, Van Gogh: The Life.
121 “事实证明，绘画的难度比我想象的要小”：来自凡·高写给弟弟西奥的信，1882年8月。凡·高那天画的那幅画是“暴风雨天气中的施维宁根海滩”。这幅画于2002年从凡·高博物馆被盗，但十多年后又被找回。
123 一篇评论欣喜若狂地：The review, by G.-Albert Aurier, was titled “Les isolés: Vincent van Gogh.”
124 荷兰的国民预期寿命：确切的数字是39.84，来自在线出版《我们世界的数据》Our World in Data (ourworldindata.org)。
124 三十五岁的高更：The Great Masters (London: Quantum Publishing, 2003).
124 “史诗级的失败”：J. K. Rowling, text of speech, “The Fringe Benefits of Failure, and the Importance of Imagination,” Harvard Gazette, June 5, 2008, online ed.
125 未来的诺贝尔经济学奖得主西奥多·舒尔茨：T. W. Schultz, “Resources for Higher Education,” Journal of Political Economy 76, no. 3 (1968): 327—47.
125 有一个自然存在的实验：O. Malamud, “Discovering One’s Talent: Learning from Academic Specialization,” Industrial and Labor Relations 64, no. 2 (2011): 375—405.
126 很快就能赶上：O. Malamud, “Breadth Versus Depth: The Timing of Specialization in Higher Education,” Labour 24, no. 4 (2010): 359—90.
126 他们犯的错误也更多：D. Lederman, “When to Specialize?,” Inside Higher Ed, November 25, 2009.
126 “匹配质量得到提升”：Malamud, “Discovering One’s Talent.”
127 经济学家史蒂芬·列维特……巧妙地利用了自己的读者群：S. D. Levitt, “Heads or Tails: The Impact of a Coin Toss on Major Life Decisions and Subsequent Happiness,” NBER Working Paper No. 22487 (2016).
127 “愿意放弃”：Levitt, in the September 30, 2011, Freakonomics Radio program, “The Upside of Quitting.”
128 “老师们倾向于离开……学校”：C. K. Jackson, “Match Quality, Worker Productivity, and Worker Mobility: Direct Evidence from Teachers,” Review of Economics and Statistics 95, no. 4 (2013): 1096—1116.
128 心理学家安琪拉·达克沃斯曾经做过一个关于“放弃”的著名实验：A. L. Duckworth et al., “Grit: Perseverance and Passion for Long-Term Goals,” Journal of Personality and Social Psychology 92, no. 6 (2007): 1087—1101. （整个新生班级由1223名新生学员组成，所以达克沃斯几乎调查了每一个人。）表3很好地总结了西点军校、斯克里普斯全国拼写大赛、常春藤盟校学生的成绩和成人教育程度中粗暴程度造成的差异。此外，达克沃思在她的书《恒毅力：激情和毅力的力量》Grit: The Power of Passion and Perseverance (New York: Scribner, 2016)中详细介绍了她的工作。
129 达克沃斯了解了“候选人整体评分系统”：一篇有关恒毅力和“候选人整体评分系统”的参考来源是：D. Engber, “Is ‘Grit’ Really the Key to Success?,” Slate, May 8, 2016.
130 “我担心，自己无意中支持了”：A. Duckworth, “Don’t Grade Schools on Grit,” New York Times, March 26, 2016.
131 “必然限制了”：Duckworth et al., “Grit: Perseverance and Passion for Long-Term Goals.”
131 1308名一年级生中有32人：M. Randall, “New Cadets March Back from ‘Beast Barracks’ at West Point,” Times Herald-Record, August 8, 2016.
132 “年少无知”：R. A. Miller, “Job Matching and Occupational Choice,” Journal of Political Economy 92, no. 6 (1984): 1086—1120.
132 “那些没有勇气去放弃的任务”：S. Godin, The Dip: A Little Book That Teaches You When to Quit (and When to Stick) (New York: Portfolio, 2007 ［Kindle ebook］).
133 坚持服役满20年：G. Cheadle (Brig. Gen. USAF ［Ret.］), “Retention of USMA Graduates on Active Duty,” white paper for the USMA Association of Graduates, 2004.
133-134 2010年发表了一部专著；“教会学员离开部队的机构”：这本专著是关于军官发展和留住的六部系列的其中之一：C. Wardynski et al., “Towards a U.S. Army Officer Corps Strategy for Success: Retaining Talent,” Strategic Studies Institute, 2010.
136 国防部长阿什顿·卡特访问西点军校：A. Tilghman, “At West Point, Millennial Cadets Say Rigid Military Career Tracks Are Outdated,” Military Times, March 26, 2016.
138 美国成年人整体平均分数：你可以将自己的恒毅力得分与其他成年人进行比较，网址是https://angeladuckworth.com/grit-scale/。
139 “奥林匹克运动员需要明白”：S. Cohen, “Sasha Cohen: An Olympian’s Guide to Retiring at 25,” New York Times, February 24, 2018.
139 最近，盖洛普公司调查了：Gallup’s State of the Global Workplace report, 2017.
