As many noticed, "The case of Yokozawa Takafumi #4" is only an extra here... but I found it on animea.net. xD And just a heads up: don't use the arrows or the "back" and "next" buttons, because they lead to a "image not found" page. If you select the page number on the list, everything works out fine. http://manga.animea.net/sekaiichi-hatsukoi-chapter-18-page-2.html#.U-gmpPh3LgA
As many noticed, "The case of Yokozawa Takafumi #4" is only an extra here... but I found it on animea.net. xD
And just a heads up: don't use the arrows or the "back" and "next" buttons, because they lead to a "image not found" page. If you select the page number on the list, everything works out fine.
http://manga.animea.net/sekaiichi-hatsukoi-chapter-18-page-2.html#.U-gmpPh3LgA