Level 1
Original sources
Level 2
Academic Research
Level 3
Online newspaper
Level 4
Specialized Newspapers (Automobile, Sustainable, Nautical, Local)
Level 5
News Condensator, News Forum
Level 6
Other
By jumping from link to link we can see that all the articles are connected through a huge copy-paste process and we can easily track down the origin of these headlines outbreak. In this connection network each link is materialized when the source is clearly stated in the article.
This article selection does not mention any source for the comparison calculation