We have posted a revision to Section V of the Linking Manual, which deals with Books. The revised section is available at https://www.scls.info/sites/www.scls.info/files/sv-books.pdf.
With this revision, the Books Searching and Matching information and the BSE information are all in one section. Previously, the Searching and Matching information was included in Section III of the Linking Manual. Section III has now been removed, because the searching and matching information has been distributed among the format-specific sections.