diff --git a/docs/src/refs.bib b/docs/src/refs.bib
index a4464e9..1990e6e 100644
--- a/docs/src/refs.bib
+++ b/docs/src/refs.bib
@@ -125,7 +125,8 @@ @Article{Eno72
   volume        = {9},
   pages         = {75--94},
   year          = {1972},
-  doi           = {0.18910/8596},
+  doi           = {10.18910/8596},
+  url           = {http://projecteuclid.org/euclid.ojm/1200693539},
   language      = {English},
   zbmath        = {3401144}
 }