While researching and analysing backlink profiles of competitors, I usually come across high PR homepage backlinks from sites with 40+ Ahrefs rank. These links are very powerful, and they are surely the kind of links I want, but I don't know how to get my backlinks on them. They are obviously part of a link selling network, not a blog network, because they look like real authority sites and they sell only footer/sidebar links. An example of such a site is www.nyaap.org. Does anyone know what network that site belongs to and how I can get my link on it? Where do top SEOs get their powerful links from (apart from private blog networks) and how can I join the networks they belong to?