non-btrfs file systems, this line type is identical to <varname>d</varname>.</para>
<para>If the subvolume already exists, no change to the quota hierarchy is made, regardless of whether the
- subvolume is already attached to a quota group or not. Also see <varname>Q</varname> below. See <citerefentry
- project='die-net'><refentrytitle>btrfs-qgroup</refentrytitle><manvolnum>8</manvolnum></citerefentry> for
- details about the btrfs quota group concept.</para>
+ subvolume is already attached to a quota group or not. Also see <varname>Q</varname> below. See
+ <citerefentry project='url'><refentrytitle url='https://btrfs.readthedocs.io/en/latest/btrfs-qgroup.html'>btrfs-qgroup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ for details about the btrfs quota group concept.</para>
<xi:include href="version-info.xml" xpointer="v228"/></listitem>
</varlistentry>
<citerefentry project='man-pages'><refentrytitle>setfacl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>getfacl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>chattr</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry project='die-net'><refentrytitle>btrfs-subvolume</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
- <citerefentry project='die-net'><refentrytitle>btrfs-qgroup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ <citerefentry project='url'><refentrytitle url='https://btrfs.readthedocs.io/en/latest/btrfs-subvolume.html'>btrfs-subvolume</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry project='url'><refentrytitle url='https://btrfs.readthedocs.io/en/latest/btrfs-qgroup.html'>btrfs-qgroup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>