Banks, William D. and Freiberg, Tristan and Maynard, James, On limit points of the sequence of normalized prime gaps. Proc. Lond. Math. Soc. (3) (2016), 515-539.

Erdős, Paul, Some remarks on number theory. Riveon Lematematika (1955), 45-48. The site's commentary credits the positive-measure theorem to Erdős under this key, but this note does not contain it (see its library card); the theorem is on p. 4 of the lecture the site keys [Er55c], P. Erdős, Some problems on the distribution of prime numbers, C.I.M.E., Teoria dei numeri (1955), https://users.renyi.hu/~p_erdos/1955-12.pdf.

Erdős, Paul, Some recent advances and current problems in number theory. Lectures on Modern Mathematics, Vol. III (1965), 196-244.

Erdős, P., On some of my problems in number theory I would most like to see solved. Number theory (Ootacamund, 1984) (1985), 74-84.

Erdős, Paul, Some of my favorite problems and results. The mathematics of Paul Erdős, I, Algorithms Combin. 13, Springer (1997), 47--67; printed p. 58: "Ricci and I proved that the set of limit points of $d_n/\log_n$ [sic] has positive measure. No doubt they are everywhere dense", stated without proof. Library home: Erdős 1997; paged at Erdős 1997, Remark (p. 58).

Goldston, Daniel A. and Pintz, János and Y\i ld\i r\i m, Cem Y., Primes in tuples. I. Ann. of Math. (2) 170 (2009), 819-862.

Hildebrand, Adolf and Maier, Helmut, Gaps between prime numbers. Proc. Amer. Math. Soc. (1988), 1-9.

Merikoski, Jori, Limit points of normalized prime gaps. J. Lond. Math. Soc. (2) (2020), 99-124.

Pintz, János, Polignac numbers, conjectures of Erdős on gaps between primes, arithmetic progressions in primes, and the bounded gap conjecture. From arithmetic to zeta-functions (2016), 367-384.

Ricci, Giovanni, Recherches sur l'allure de la suite $\{p_{n+1}-p_n/\log p_n\}$. Colloque sur la Théorie des Nombres, Bruxelles, 1955 (1956), 93-106.

Westzynthius, E., Über die Verteilung der Zahlen, die zu den n ersten Primzahlen teilerfremd sind. Commentat. Phys. Math. (1931), 1-37.