Google Books useful in my Knight's Tour Research

I've recently found that some important and obscure texts on knight's tours are now available in Google Books. The following are links to four of them:

Warnsdorf 1823

http://books.google.co.uk/books?id=w5FZAAAAYAAJ&printsec=frontcover&dq=h.+c.+von+warnsdorf&hl=en&sa=X&ei=2QZmU9-jJIaXO8-hgKgL&ved=0CDEQ6AEwAA#v=onepage&q=h.%20c.%20von%20warnsdorf&f=false

Kafer 1842

http://books.google.co.uk/books?id=si1RAAAAcAAJ&printsec=frontcover&dq=Kafer+1842&hl=en&sa=X&ei=3nfbU9PFO8PE7AbEooGYDA&ved=0CCEQ6AEwAA#v=onepage&q&f=false

Perenyi 1842

http://books.google.co.uk/books?id=jf0UAAAAYAAJ&printsec=frontcover&dq=perenyi+1842&hl=en&sa=X&ei=dvtlU7fFNcGJPdbZgPgK&ved=0CDEQ6AEwAA#v=onepage&q&f=false

Jaenisch's Treatise 1862

http://books.google.co.uk/books?id=UMpUAAAAYAAJ&pg=PP11&dq=Jaenisch+Traite&hl=en&sa=X&ei=lfLKU-O-O-Se7Aau6YCwDA&ved=0CDAQ6AEwAw#v=onepage&q=Jaenisch%20Traite&f=false

A problem with the Warnsdorf and Kafer books is that the Google versions do not reproduce the figures!
However I found a copy of the Kafer sheet of diagrams elsewhere on the web, and I was able to obtain a copy of the Warnsdorf tours through the kindness of Cleveland Public Library, Ohio.
More on this subsequently.

There are probably may other titles to be found by a search in Google Books.
Kafer details added in update of this page 1 Aug 2014.