Besides his book On the Origin of Species, Charles Darwin wrote many other significant works. Provide the names of three additional significant books or articles that were written by Darwin and provide a description of the subject matter and significant contribution of each of these.
Please provide the source(s) of information for your answer. For books, magazines and/or journal articles, give the title of book/paper, page numbers, year of publication and author name(s). For websites, please provide the URL(s).