Hayate no Gotoku! Chapter 192:Who Would Say a Joke That He Likes a Girl Who is Full of Opens? (スキのある女の子がスキというダジャレを言うのはダレジャ,Suki no aru on'nanoko ga suki to iu dajare o iu no wa dareja?)
Additionally, a character strongly resembling Holo can be seen on the cover of the book.
When Nagi and Chiharu talking about Idiots, Tests, and Spice, the scene from Idiots, Tests, and Summoned Beasts when Hideyoshi Kinoshita disguise as Yuuko Kinoshita was revealed.
While at the Video Arcade, Nagi and Chiharu both play a game called "Collage Kart". This is a parody of the game Mario Kart.
While playing the arcade game with Nagi, Chiharu remarks that she'll become a charming adult like Fujiko-chan. This is a reference to the character Fujiko Mine from the series Lupin III.