Credits Shortcode plugin allows to add Source Link or Via Link for a post or a page. Shortcodes can be added directly or can be added using the button in the WordPress Editor window.
[credits link=”http://example.com” type=”source”] Source Name [/credits]
[credits link=”http://example.com” type=”via”] Via Name [/credits]
This plugin is available for download to be used on your WordPress self-hosted installation.