1. Clark Kimberling in Emmy Noether, A Tribute to Her Life and Work; James W. Brewer and Martha K. Smith, ed.; Marcel Dekker, Inc.
2. E. Noether, Invariante Variationsprobleme, Nachr. d. König. Gesellsch. d. Wiss. zu Göttingen, Math-phys. Klasse (1918), 235–257.
3. Auguste Dick, Emmy Noether (1882 – 1935), Birkhauser 1981; English translation by H. I. Blocher.
4. M. A. Tavel, Transport Theory and Statistical Physics 1(3), 1971, 183–207; English translation of Ref. [2].
5. Felix Klein, Gesammelte mathematische Abhandlungen, erster band pp. 568–585. The correspondence between David Hilbert and Felix Klein cited below in Ref. [6] is included here pp. 551–567. On p. 559 Klein writes that he discussed with Noether and found that she already had written a paper on this the year before but had not published it.