diff --git a/libconfig.spec b/libconfig.spec
index ce34cf5..0b07bbc 100644
--- a/libconfig.spec
+++ b/libconfig.spec
@@ -4,6 +4,8 @@ Release:        8
 Summary:        C/C++ Configuration File Library
 License:        LGPLv2+
 URL:            http://www.hyperrealm.com/libconfig/libconfig.html
+# This tarball comes from libconfig-1.7.2/docs/dist/libconfig-1.7.2.tar.gz
+# in archive(https://github.com/hyperrealm/libconfig/archive/v1.7.2.tar.gz)
 Source0:        https://github.com/hyperrealm/libconfig/archive/%{name}-%{version}.tar.gz
 
 Source1:        libconfig.pdf