4-1 Newspaper Wars, Joseph Pulitzer, William Randolph Hearst:
http://projects.vassar.edu/1896/nypress.html
http://spartacus-educational.com/Jpulitzer.htm
http://spartacus-educational.com/USAhearst.htm
4-2 Yellow Journalism: http://www.pbs.org/crucible/frames/_journalism.html
4-3 Mark Twain: http://www.biography.com/people/mark-twain-9512564
4-4 The Spanish-American War: http://www.u-s-history.com/pages/h3617.html
4-5 The Panama Canal: http://geography.howstuffworks.com/central-america/panama-canal.htm/printable
4-6 Pancho Villa: http://history1900s.about.com/cs/panchovilla/p/panchovilla.htm
4-7 Theodore Roosevelt: http://www.whitehouse.gov/about/presidents/theodoreroosevelt
4-8 The RMS Titanic: http://www.eyewitnesstohistory.com/titanic.htm
11 things the Titanic movie got wrong about the real-life tragedy: https://www.bustle.com/p/11-things-the-titanic-movie-got-wrong-about-the-real-life-tragedy-66287
Video - National Geographic How the Titanic Sank: https://www.youtube.com/watch?v=HyLjw0GAQoY
Facts about Theodore Roosevelt:
http://mentalfloss.com/article/545665/facts-about-president-theodore-teddy-roosevelt