The CSL Style Repository may not contain any (non-excepted) duplicate ISSNs

expected: {}
     got: {"1478-0941"=>["bulletin-of-geosciences", "journal-of-systematic-palaeontology"]}

(compared using ==)

Diff:
@@ -1 +1,2 @@
+"1478-0941" => ["bulletin-of-geosciences", "journal-of-systematic-palaeontology"],

(Hancké et al. 2007; CSL search by example 2012)
(Mares 2001; Fenner et al. 2019)

---

CSL search by example. 2012. Citation Style Editor. World Wide Web Address: http://editor.citationstyles.org/searchByExample/
Fenner, M., Crosas, M., Grethe, J.S., Kennedy, D., Hermjakob, H., Rocca-Serra, P., Durand, G., Berjon, R., Karcher, S., Martone, M. & Clark, T. 2019. A data citation roadmap for scholarly data repositoriesScientific Data 6(1), 28. DOI 10.1038/s41597-019-0031-8
Hancké, B., Rhodes, M. & Thatcher, M. (eds). 2007. Beyond Varieties of Capitalism : Conflict, Contradiction, and Complementarities in the European Economy Oxford University Press, Oxford and New York.
Mares, I. 2001. Firms and the welfare state: When, why, and how does social policy matter to employers? In: Hall, P.A. & Soskice, D. (eds) Varieties of Capitalism. The Institutional Foundations of Comparative Advantage Oxford University Press, New York, 184–213.