diff --git a/doc/src/sgml/dfunc.sgml b/doc/src/sgml/dfunc.sgml
index a87e47a104..a635767621 100644
--- a/doc/src/sgml/dfunc.sgml
+++ b/doc/src/sgml/dfunc.sgml
@@ -208,7 +208,7 @@ gcc -G -o foo.so foo.o
  <tip>
   <para>
    If this is too complicated for you, you should consider using
-   <ulink url="http://www.gnu.org/software/libtool/">
+   <ulink url="https://www.gnu.org/software/libtool/">
    <productname>GNU Libtool</productname></ulink>,
    which hides the platform differences behind a uniform interface.
   </para>
diff --git a/doc/src/sgml/installation.sgml b/doc/src/sgml/installation.sgml
index 552303e211..53f36cebba 100644
--- a/doc/src/sgml/installation.sgml
+++ b/doc/src/sgml/installation.sgml
@@ -239,7 +239,7 @@ su - postgres
       class="osname">Linux</systemitem>, <systemitem class="osname">NetBSD</systemitem>,
       <systemitem class="osname">Solaris</systemitem>), for other systems you
       can download an add-on package from <ulink
-      url="http://www.gnu.org/software/gettext/"></ulink>.
+      url="https://www.gnu.org/software/gettext/"></ulink>.
       If you are using the <application>Gettext</application> implementation in
       the <acronym>GNU</acronym> C library then you will additionally
       need the <productname>GNU Gettext</productname> package for some