--- a/thys/Paper/document/root.bib	Tue May 17 05:14:41 2016 +0100
+++ b/thys/Paper/document/root.bib	Tue May 17 10:53:34 2016 +0100
@@ -34,7 +34,7 @@
 @book{Pierce2015,
   author = {B.~C.~Pierce and C.~Casinghino and M.~Gaboardi and
             M.~Greenberg and C.~Hri\c{t}cu and 
-            V.~Sjoberg and B.~Yorgey},
+            V.~Sj\"{o}berg and B.~Yorgey},
   title = {{S}oftware {F}oundations},
   year = {2015},
   publisher = {Electronic textbook},