diff --git a/content/3.defense-systems/pd-t7-3.md b/content/3.defense-systems/pd-t7-3.md
index 00a3d2028a56c6ab4833ed822d1f6249a61a02d0..2672d4863fb216850c5a11fcae3487791cb25ed0 100644
--- a/content/3.defense-systems/pd-t7-3.md
+++ b/content/3.defense-systems/pd-t7-3.md
@@ -19,7 +19,7 @@ relevantAbstracts:
 # PD-T7-3
 ## Description
 
-PD-T7-3 systems were discovered to be anti-phage systems during an experimental screen performed on *E. coli* strains ref{doi=10.1038/s41564-022-01219-4}
+PD-T7-3 systems were discovered to be anti-phage systems during an experimental screen performed on *E. coli* strains :ref{doi=10.1038/s41564-022-01219-4}
 
 ## Molecular mechanisms
 As far as we are aware, the molecular mechanism of PD-T7-3 is unknown.