The main character, Blue van Meer, is a high school student. During her study hall period in the library, she describes how she spies on her fellow classmates:
...[I] slipped into row 500 and then the densest section of row 900, Biography, where I repositioned some of the larger books from row 600 to the holes between the shelves, in order to avoid detection. (Librarian Hambone, if you're reading this, I apologize for the biweekly repositioning of H. Gibbons' bulky African Wildlife  from its proper place in the 650s to just above Mommie Dearest [Crawford, 1978] and Notorious: My Years with Cary Grant [Drake, 1989]. You weren't going mad.)
What caught my eye was her saying the proper place for a book called African Wildlife is in Dewey 650s. Presuming this book is actually about African wildlife, the 650s isn't even close (by Dewey standards). It should be more like 591.96, which is in stark contrast to said 650s.
The reason this stood out is that Calamity Physics is loaded with literary references - everything from the classics to technical manuals to contemporary romance fiction to journal articles. This author must have spent Much Time in a library researching this book, as shown by her excellent use of these references to aptly describe characters and situations (unless, of course, every single one of them was just made up).
For example, when describing being honest with her father:
I had to confront him. Otherwise, the lie could wear me away (see "Acid Rain on Gargoyles," Conditions, Eliot, 1999, p. 513).
When describing a classmate named Jade:
Jade was the terrifying beauty (see "Tawney Eagle," Magnificent Birds of Prey, George, 1993).
And describing another student's bedroom:
We walked by what had to be Bethany Louise's room, painted gum pink, a pile of clothes on the floor (see "Mount McKinley," Almanac of Major Landmarks, 2000 ed.).
There were about one of these references every other page, which means this 500 page book had a lot of references. So I'm surprised that the Dewey numbers were so far off (although, maybe the author naming the librarian "Hambone" belies a disdain of libraries?).
And since I'm talking about, here's my overall impression of the book: I enjoyed pages 1-100 and 300-500, but the two hundred pages in between kind of dragged. Lots of high schooly angst and controversy, whereas the rest of the book held interesting plot and character interactions - not to mention an underground conspiracy organization. I ended up liking it, but had to force my way through at some points.