There are numerous other sources for finding useful books and other publications. Some of the most well-known online search engines are listed below.
Google – Go to Google seach and select the Book search option. Enter the term Sierra County in quotes. The search results will show a long list of matching publications. Some of the historical books (government reports and those books with expired copyrights) can be viewed online.
Library of Congress – All copyrighted books, magazines, newspapers, etc, are described in a searchable online catalog. They also have online digital collections that include old photographs.
Family History Books – Digitalized books can be searched for and viewed online. Provided by the FamilySearch website. If you don't initially find anything interesting, be sure to check again at a later date. LDS is constantly adding to this collection at a rate of about 10,000 pages per day.