基础积累，来自其他网站的链接

http://wenku.baidu.com/link?url=aL3tQayVpkcrncKLNAOKIsUqXCAkL-E8KnwFSATfQnQgddysfRxY1Ldr-1i3fRKCifxxf6PbZFgSJLwGhka9ne9CGQht8UINp5QT9DXQ-Yi