I have to agree with parent here. In writing, if the source is sufficiently well-known, or even within the same genre, then direct citation is not really necessary. Modernists and Post-Mod poets are well known for this.
In the case of little known, or outside references, a subtle hint at origin is often enough and satisfies the conscience of the writer. There are instances, when a citation is appropriate. Such as an article from AP (I've written several poems based on such, and have included citations at the bottom of the page. Not only because I lift quotations, but because the original article provides a level of detail and understanding that is not appropriate to the poem itself). In many cases, a simple reference is less obtrusive and more effective, however.
At any rate, the real issue is representing someone else's work as one's own, without modification or reinterpretation to warrant it being a "new work," which is what our teen-aged author has perpetrated.
I know nobody RTFA, but has anyone read TFB?