diff --git a/astropy/io/votable/exceptions.py b/astropy/io/votable/exceptions.py
index d2986af26f7..40d16db7230 100644
--- a/astropy/io/votable/exceptions.py
+++ b/astropy/io/votable/exceptions.py
@@ -318,7 +318,7 @@ class W02(VOTableSpecWarning):
 
     **References**: `1.1
     <http://www.ivoa.net/documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#sec:name>`__,
-    `XML Names <http://www.w3.org/TR/REC-xml/#NT-Name>`__
+    `XML Names <https://www.w3.org/TR/xml-names/>`__
     """
 
     message_template = "{} attribute '{}' is invalid.  Must be a standard XML id"
diff --git a/docs/install.rst b/docs/install.rst
index e203d9709d4..8ae8d4bbcd1 100644
--- a/docs/install.rst
+++ b/docs/install.rst
@@ -379,41 +379,7 @@ The C libraries currently bundled with ``astropy`` include:
 - `expat <https://libexpat.github.io/>`_ see ``cextern/expat/README`` for the
   bundled version. To use the system version, set ``ASTROPY_USE_SYSTEM_EXPAT=1``.
 
-
-Installing ``astropy`` into CASA
---------------------------------
-
-If you want to be able to use ``astropy`` inside `CASA
-<https://casa.nrao.edu/>`_, the easiest way is to do so from inside CASA.
-
-First, we need to make sure `pip <https://pip.pypa.io>`__ is
-installed. Start up CASA as normal, and then type::
-
-    CASA <2>: from setuptools.command import easy_install
-
-    CASA <3>: easy_install.main(['--user', 'pip'])
-
-Now, quit CASA and re-open it, then type the following to install ``astropy``::
-
-    CASA <2>: import subprocess, sys
-
-    CASA <3>: subprocess.check_call([sys.executable, '-m', 'pip', 'install', '--user', 'astropy'])
-
-Then close CASA again and open it, and you should be able to import ``astropy``::
-
-    CASA <2>: import astropy
-
-Any ``astropy`` affiliated package can be installed the same way (e.g. the
-`spectral-cube <https://spectral-cube.readthedocs.io>`_ or other
-packages that may be useful for radio astronomy).
-
-.. note:: The above instructions have not been tested on all systems.
-   We know of a few examples that do work, but that is not a guarantee
-   that this will work on all systems. If you install ``astropy`` and begin to
-   encounter issues with CASA, please look at the `known CASA issues
-   <https://github.com/astropy/astropy/issues?q=+label%3ACASA-Installation+>`_
-   and if you do not encounter your issue there, please post a new one.
-
+.. _install_astropy_nightly:
 
 Installing pre-built Development Versions of ``astropy``
 --------------------------------------------------------
diff --git a/docs/io/votable/references.txt b/docs/io/votable/references.txt
index 42645e18054..e4975684c30 100644
--- a/docs/io/votable/references.txt
+++ b/docs/io/votable/references.txt
@@ -6,7 +6,7 @@
 .. _FIELDref: http://www.ivoa.net/documents/REC/VOTable/VOTable-20040811.html#ToC31
 .. _FITS: https://fits.gsfc.nasa.gov/fits_documentation.html
 .. _GROUP: http://www.ivoa.net/documents/REC/VOTable/VOTable-20040811.html#ToC31
-.. _ID: http://www.w3.org/TR/REC-xml/#id
+.. _ID: https://www.w3.org/TR/xml-id/
 .. _INFO: http://www.ivoa.net/documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#ToC19
 .. _LINK: http://www.ivoa.net/documents/REC/VOTable/VOTable-20040811.html#ToC22
 .. _multidimensional arrays: http://www.ivoa.net/documents/REC/VOTable/VOTable-20040811.html#ToC12