Unfortunately, this article seems quite incorrect. It makes it look like iBGP and eBGP are different protocols while they are the same with a slightly different set of rules. Notably, prefixes exchanged by iBGP definitely have an AS path (which can be empty, but usually it is not as most of the routes come from outside the AS). This is not the only error. The definition for iBGP/eBGP is incorrect too: iBGP let's two routers in the same AS exchange routes, while eBGP does the same for two routers in different AS.