Still the American Frontier: Fourth (4th) Amendment Litigation

Read the article titled, “Still the American Frontier: Fourth (4th) Amendment Litigation” located at http://wispd.org/attachments/article/220/Still%20the%20American%20Frontier-%20Fourth%20Amendment%20Litigation.pdf. Explain in your own words situations in which the plain view doctrine applies. List other exceptions to this doctrine not mentioned in the text? Please support your response.