@article{Grzelak:201973, author = "Grzelak, Grzegorz", title = "{Measurement of the $\psi(2S)$ to $J/\psi$ cross section ratio in photoproduction with the ZEUS detector at HERA}", doi = "10.22323/1.340.0921", journal = "PoS", year = 2019, volume = "ICHEP2018", pages = "921" }