Sketch is the most popular one-stop application of vector drawing on Mac platform, developed by Sketch B.V. from Netherlands in 2010. Compared to other vector drawing software (such as Adobe Illustrator), it has the advantage of being easy to use (all the tools you need are near at hand), has a low learning curve, and saves designers a lot of time and effort. To some extent, we can think of it as a lightweight edition of Adobe Illustrator.

Here, AppNee provides you two really excellent and free-to-use icons material packages. One contains 1000+ beautiful and colorful icons and the other has 2000+. Both of them were released in 4 kinds of vector image formats (AI, PSD, Sketch, PNG) with high quality.

PrintLayout is a lightweight and free layout designing & printing program from China, specially designed for user interface sketch design of software development's initial stage.

Wiley Publishing is a publisher with a long history, its Bible series of books enjoy great popularity. Google SketchUp and SketchUp Pro 7 Bible provides detailed information on full applications of Google SketchUp from basic to advanced, which will help you become skilled professional from novice. Even for people who are familiar with SketchUp, they could find useful parts from this book.