1. Apple. 2017. Human Interface Guidelines. https://developer.apple. com/ios/human-interface-guidelines/ Apple. 2017. Human Interface Guidelines. https://developer.apple. com/ios/human-interface-guidelines/
2. Apple. 2017. UI Design Do’s and Don’ts. https://developer.apple.com/ design/tips/ Apple. 2017. UI Design Do’s and Don’ts. https://developer.apple.com/ design/tips/
3. Apple Developer. 2017. UIKit Framework. https://developer.apple. com/documentation/uikit Apple Developer. 2017. UIKit Framework. https://developer.apple. com/documentation/uikit
4. Constraint cascading style sheets for the Web
5. Making the web easier to see with opportunistic accessibility improvement