@article{PLUTO:1987tzi, author = "Berger, Christoph and others", collaboration = "PLUTO", title = "{Measurement and Analysis of the Reaction $\gamma \gamma \to \pi^+ \pi^- \pi^+ \pi^-$}", reportNumber = "DESY-87-173", doi = "10.1007/BF01624356", journal = "Z. Phys. C", volume = "38", pages = "521", year = "1988" }