diff --git a/pdf/book.tplx b/pdf/book.tplx
index eab07cc..965454d 100644
--- a/pdf/book.tplx
+++ b/pdf/book.tplx
@@ -30,5 +30,7 @@
     ((* block tableofcontents *))\tableofcontents((* endblock tableofcontents *))
 ((* endblock predoc *))
 
-
+((* block markdowncell scoped *))
+((( cell.source | citation2latex | strip_files_prefix | convert_pandoc('markdown+tex_math_double_backslash', 'json',extra_args=[]) | resolve_references | convert_pandoc('json','latex', extra_args=["--chapters"]) )))
+((* endblock markdowncell *))
 
diff --git a/pdf/merge_book.py b/pdf/merge_book.py
index c46cb44..b50ce6c 100644
--- a/pdf/merge_book.py
+++ b/pdf/merge_book.py
@@ -41,8 +41,6 @@ def merge_notebooks(outfile, filenames):
 
 if __name__ == '__main__':
     with open('book.ipynb', 'w', encoding='utf-8') as f:
-        '''merge_notebooks(f,
-            ['../04-One-Dimensional-Kalman-Filters.ipynb'])'''
 
         merge_notebooks(f,
             ['./tmp/00-Preface.ipynb',