Spell Unix, not UNIX.
diff --git a/Doc/lib/libunix.tex b/Doc/lib/libunix.tex
index 239f426..05db4a9 100644
--- a/Doc/lib/libunix.tex
+++ b/Doc/lib/libunix.tex
@@ -1,4 +1,4 @@
-\chapter{UNIX Specific Services}
+\chapter{Unix Specific Services}
The modules described in this chapter provide interfaces to features
that are unique to the \UNIX{} operating system, or in some cases to
diff --git a/Doc/libunix.tex b/Doc/libunix.tex
index 239f426..05db4a9 100644
--- a/Doc/libunix.tex
+++ b/Doc/libunix.tex
@@ -1,4 +1,4 @@
-\chapter{UNIX Specific Services}
+\chapter{Unix Specific Services}
The modules described in this chapter provide interfaces to features
that are unique to the \UNIX{} operating system, or in some cases to