Quote from unnes
There were two references to Death Note, actually. The first was when Nagi is putting her manga back on the bookshelf. You can see that she drew in a notebook entitled "Death Note". That's the obvious one.
Later on, when she's plotting on being cold to Hayate, she says "Just as planned!" with a sneer on her face. This is also straight out of Death Note, from the scene when Kira resumes possession of the notebook.
The first one was so clear it didn't need a note (you can read the words "Death Note" with no problem), and I thought the second, while somewhat subtle, would be recognizable to fans of the series.
Lol! I see them now...
I'm really not the visual kind... so I missed the first one. It took me 1 year after I finished wipeout 2097 for example to notice that the type of the weapon I get depended on the color of the power up node I run on... (And it was my sister that told me about it lol).
The second one on the other hand I noticed it, but I didn't think about it to much... Because without the first reference it would have felt as if I said that bleach have a Death Note reference when they talk about shinigami (or vice versa)... I mean Kirra isn't the only guy in a manga that made that kind of sneer.
But once you see the first reference it becomes obvious that it was the intention of the author.