Another alternative to save money and obtaining the materials you are required are e-textbooks. The article "E books rewrite the rules of education" states that, alternately to spending a lot of money on textbooks, you can purchase an e-textbook at a small amount of the cost. With the growth of digital applications for iPhone, and gadgets like the Amazon kindle, e-textbooks are not an innovation, but have been "gaining momentum". According to the article " Are textbooks obsolete?", publishers and editorials are concerned about the issue of expensive textbooks. "The expense of textbooks is a concern for students, and e-textbooks, address the face of the issue, Williams says " As publishers we understand the high cost of these materials, and the electronic format permit us diminish the general expense of our content to the market". E-textbook applications facilitate similar experiences to physical textbooks by allowing the user to highlight and take notes in-page. These applications also extend textbook learning by providing quick definitions, reading the text aloud, and search functionality.