"The Feynman Lectures on Physics (volume I; lecture 3: "The Relation of Physics to Other Sciences")". Book by Richard P. Feynman, Robert B. Leighton and Matthew Sands, 1964.
"The Feynman Lectures on Physics". Physics textbook by Richard P. Feynman, Robert B. Leighton, and Matthew Sands, volume I; lecture 1, "Atoms in Motion"; section 1-2, "Matter is made of atoms"; p. 1-2, 1964.
Richard P. Feynman, Robert B. Leighton, Matthew Sands (2015). “The Feynman Lectures on Physics, Vol. I: The New Millennium Edition: Mainly Mechanics, Radiation, and Heat”, p.67, Basic Books