Anybody knows what are they referring to? I couldn't find an author with a name like that? http://www.mangago.me/read-manga/mitsubana/mb/Mitsubana/Chapter_2_(end)/3/

The author of the drawing is Watanabe Asia, the same one of that manga you linked. About piasu comics, I think it is a reference to the Boy's Pierce, that is published under Junet. Here is a list: https://www.mangaupdates.com/publishers.html?pubname=Boy%26%23039%3Bs+Pierce

Thanks will check out the link ^ ^