diff --git a/Makefile.PL b/Makefile.PL
index fd3cdc8..b825588 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -6,9 +6,9 @@ WriteMakefile(
     NAME              => 'Pg::Checksource',
     VERSION_FROM      => 'lib/Pg/Checksource.pm', # finds $VERSION
     PREREQ_PM         => {
-        File::HomeDir                   => 0,
-        Pg::Parser                      => 0,
-        Array::Stream::Transactional    => 1.02,
+        "File::HomeDir"                   => 0,
+        "Pg::Parser"                      => 0,
+        "Array::Stream::Transactional"    => 1.02,
     }, # e.g., Module::Name => 1.1
     ($] >= 5.005 ?     ## Add these new keywords supported since 5.005
       (ABSTRACT_FROM  => 'lib/Pg/Checksource.pm', # retrieve abstract from module