diff --git a/bib/glossaries/index/names.bib b/bib/glossaries/index/names.bib
index 674a81c..9c5ff11 100644
--- a/bib/glossaries/index/names.bib
+++ b/bib/glossaries/index/names.bib
@@ -15,6 +15,10 @@
 % if the entry label is printable, it can be used.
 % An explicit name field is required for escaped characters (umlauts etc.)
 
+@index{ernst_mach,
+    name={Mach},
+    firstname={Ernst},
+}
 @index{edward_tufte,
     name={Tufte},
     firstname={Edward},