1. F. W. Bessel came upon these functions in discussion of planetary perturbations, and made the first tables of 𝐽₀(𝑥) and 𝐽₁(𝑥); Akad. d. Wissen., Berlin, Math. Klasse, Abh. for the year 1824, Berlin, 1826. The name “Bessel’s function” and the notation 𝐽_{𝑛}(𝑥) are due to O. Schlömilch, Z. Math. Phys., v. 2, 1857.
2. D. Bernoulli, Akad. Nauk. Leningrad, Commentarii, v. 6 for the year 1732 and 1733, 1738, p. 116-119. See also G. A. Maggi, Accad. d. Lincei, Atti, s. 3, Transunti, v. 4, 1880, p. 259-263
3. and M. Bôcher, New York Math. So., Bull., v. 2, 1893, p. 107-109.
4. H. Weber, J.f. d. reine u. angew. Math., v. 76, 1873, p. 9
5. Math. Annalen, v. 6, 1873, p. 148.