Tonnura-san - Vol. 4 Ch. 20 - Event with Ichino

[MangaDex]

 

[Markgraf]

Seconding Uskon's remark at the end. Ichino is one of the hottest female middle school characters I've encountered. She is glorious in this chapter. Nabiki is pretty tasty looking too.

 

[GondiTheCat]

According to keikaku.
Looks like Ichino is diving into the deep dark world of otaku. Welcome to the club, girl!

 

[spidersonbikes]

Yay Idolmaster cosplay

 

[BakedBanana]

"Would the armpit maiden also like to take part?" (Page 13)

LOL, Reimu is indeed known for that..

Also here's all the references I could find, there is definitely more:

Character	Reference	Page #
Ichino	Mato Kuroi (Black Rock Shooter)	Page 2
Nabiki	Reimu (Touhou)	Page 4
Nabiki	Yoko (Gurren Lagann)	Page 5
Random crying guy	Kaiji (Kaiji: Ultimate Survivor)	Page 7
Gloomy friend	Hatsune Miku	Page 8
Random idol girls x2	Yayoi (The iDOLM@STER) Haruka (The iDOLM@STER)	Page 10
Random girls x2	Yuno (Hidamari Sketch) Marisa (Touhou)	Page 20
Random girl	Ika Musume (Shinryaku! Ika Musume)	Page 21