[1]: http://hgbook.red-bean.com/hgbookch3.html
[2]: http://hgbook.red-bean.com/hgbookch1.html
[3]: http://hgbook.red-bean.com/hgbookch1.html#tailhgbookch1.html
[1]: http://hgbook.red-bean.com/hgbookch3.html
[2]: http://hgbook.red-bean.com/hgbookch1.html
[3]: http://hgbook.red-bean.com/hgbookch1.html#tailhgbookch1.html