Rule: Avoid multiple outgoing links
Try to reduce external links on your page.
If multiple links with the same external url are given, try to mark as much as possible uris with the rel="nofollow" attribute to increase your "link juice".
Google gives every site a total score and every link will reduce the score; except links marked with rel="nofollow".
The higher the score of the document the higher are the backlink quality for the targeted site. This term is equal to the rule Avoid multiple internal links.