diff --git a/data/astro.md b/data/astro.md
index bcaa5a3951ed3f268fa793bcb194158e0eff4f36..3b7491c9b4d9e0ca7412a3f83230d6810af6ecaa 100644
--- a/data/astro.md
+++ b/data/astro.md
@@ -41,7 +41,7 @@ and reducing spurious surface tensions that are present in a traditional
 ### GIZMO (MFM)
 
 Bert Vandenbrouke has also implemented a publicly-available GIZMO-like scheme
-([Hopkins 2015](http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1409.7395)
+([Hopkins 2015](http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1409.7395))
 in SWIFT. This promises higher-accuracy hydrodynamics, but with the natural
 adaptivity of SPH.