Einstein’s letter of August 4, 1946: Document 70-960 in the Albert Einstein Archives.

any other of his more intimate friends and colleagues: The Physics Department at Princeton University held a symposium on relativity in honor of Einstein’s seventieth birthday. Gamow was among the many who were invited. (A letter from Assistant to the Chairman at Princeton Paul Busse on March 15, 1949, informs him of travel arrangements.) However, Gamow’s name does not appear on the list of people accepting the invitation, from March 17, 1949.

“The introduction of the ‘cosmological member’”: Einstein 1955, p. 127.

“If Hubble’s expansion had been discovered”: Einstein 1955, p. 127.

included a supplementary footnote: Pauli 1958, p. 220.