refextract: authors separated by semicola

[fschwenn]

references like "T. Venumadhav; F.-Y. Cyr-Racine; K. N. Abazajian; and C. M. Hirata: Sterile neutrino dark matter: Weak interactions in the strong coupling epoch, Phys. Rev. D94, 043515 (2016), 1507.06655." are split at every ";" creating additional nonsense references with just an author. I would propose to not split strings off without any number in it.