Blackdog Media
Classic Reader: Charlotte M. Yonge
This site provides links to 18 novels by Charlotte M. Yonge. These include The Armourer's Prentices, Countess Kate, The Heir of Redclyffe, and The Little Duke.
Open Library of the Internet Archive
Open Library: The Little Duke
This ebook version of Charlotte Mary Yonge's The Little Duke has been made available in multiple formats by the Open Library. Editions of the full novel, organized by year of publication, may be accessed here.