path('book/<slug:slug>/txt', views.book_txt, name="documents_book_txt"),
path('book/<slug:slug>/html', views.book_html, name="documents_book_html"),
path('book/<slug:slug>/epub', views.book_epub, name="documents_book_epub"),
+ path('book/<slug:slug>/epubcheck', views.book_epubcheck, name="documents_book_epubcheck"),
path('book/<slug:slug>/mobi', views.book_mobi, name="documents_book_mobi"),
path('book/<slug:slug>/pdf', views.book_pdf, name="documents_book_pdf"),
path('book/<slug:slug>/pdf-mobile', views.book_pdf, kwargs={'mobile': True}, name="documents_book_pdf_mobile"),