A search on http://books.google.com/ provides almost 3000 references to Keyserling (k)!   These include books and articles by and about Keyserling (k).   Some of the items are visible in Google, others are copyrighted and available by subscription or  on request.  When searching under Keyserling make sure to go to 'advanced book search' to remove from the search books by:Leon, Thomas, Harriet, Mary,Harriet, Dublin as these are not Keyserling blood relatives. These names should be put into the line 'without the words' and without the use of commas.