Let me just make another point: in your first article, it called the proton an elementary particle. I pointed out this was wrong (because it is). You suggest that I not criticise the article, but your second link pointedly reveals that the proton is made up of quarks. That means it's not an elementary particle, in direct contradiction to your first link. Are you sure you understand your links, if you cannot see this point?
The proton and neutron in fact contains all types of quark, and antiquark, although all but the two up and one down quarks are "sea" quarks -- as in, they appear at random, eg due to the Uncertainty Principle, before disappearing again just as quickly, but are still important to understand the structure of the particle.