[racket] Scribble rendering difference

Should scribble/lp  documents render differently in pdf than in text or 
html?
This is the text output of the example in the lp documentation:

Literate programs have chunks of code, like this one:
**this line is missing in pdf**
<f> ::=

   (define (f x)
     <fs-body>)

and this one:
**this line is missing in pdf**
<fs-body> ::=

   (* x x)

that, when assembled, produce a complete program, in this case:

   (define (f x)
     (* x x))

Cheers - Stuart McLuckie