Label placed at end of \book not recognised in \paper

[Tom van der Hoeven]

Hi all,
If a label placed at the end of a book, it is not recognised in the 
paper description.
If it is placed before the last score, it is recognised.
Is that correct?
Tom
-------------------------
\version "2.18.0"
\paper{
    %#(define page-breaking ly:page-turn-breaking)
    print-first-page-number = ##t
    top-margin = 3.0
    bottom-margin = 3.0
    before-title-space = 10.0
    after-title-space = 5.0
    oddHeaderMarkup = \markup \fill-line {
                " "
                \on-the-fly #not-first-page \fromproperty 
#'header:instrumentHeader
                \on-the-fly #print-page-number-check-first 
\fromproperty #'page:page-number-string }
    evenHeaderMarkup = \markup \fill-line {
                " "
                \on-the-fly #not-first-page \fromproperty 
#'header:instrumentHeader
                \on-the-fly #print-page-number-check-first 
\fromproperty #'page:page-number-string }

    oddFooterMarkup = \markup {
    \column {
      \fill-line {
        \line {
          Blz
          \on-the-fly #print-page-number-check-first
          \fromproperty #'page:page-number-string
          "van  " \concat {\page-ref #'npages "0" "?"}
        }
      }
    }
  }
    ragged-last-bottom = ##t
    %    first-page-number = 2
}    %% fin paper

\header { tagline = ##f }
\book {
  \label #'firstScore
  \score {
    {
      c'1
      \pageBreak \mark A \label #'markA
      c'1
    }
  }
  \markup { The first score begins on page \page-ref #'firstScore "0" "?" }
  \markup { Mark A is on page \page-ref #'markA "0" "?" }
  \label #'npages
}