Yoren Chang

<p>Thanks to <a href="https://github.com/WebDevStudios/Taxonomy_Single_Term" rel="nofollow ugc">Taxonomy_Single_Term</a>, a library created by <a href="http://webdevstudios.com/" rel="nofollow ugc">WebDevStudios</a>, it made my work much easier on creating this plugin.</p>
<p>With Categories Metabox Enhanced, you can:</p>
<ul>
<li>Change the built-in Categories metabox/panel to a single term UI, which means replacing the checkboxes with radio buttons or a select drop-down.</li>
<li>Apply the single term UI to other hierarchical taxonomies in the plugin’s Settings page.</li>
<li>Customized the single term UI by setting these options:
<ul>
<li>Priority and position of the metabox placement.</li>
<li>Title of the metabox.</li>
<li>If child-terms should be indenting.</li>
<li>If adding of new terms from the metabox is enable.</li>
</ul>
</li>
</ul>


Categories Metabox Enhanced

Replace the checkboxes with radio buttons or a select drop-down in the built-in Categories metabox and Gutenberg sidebar panel.

Nilambar Sharma

<h3>Source Affix</h3>
<p>This is right plugin for you if you want to add source link to your post. It adds separate meta box for the input of source text. You can use this feature to any Post or Page. Even more, it also supports custom post type. Several plugin settings are also available. You can show sources in comma separated form or in an unordered list. You can append or prepend source to the content.</p>


Source Affix

A plugin for adding source links to your Post. Supports Page and Custom Post Type also.

Categories Metabox Enhanced vs Source Affix