Update Drain.md

Jamie Zhu · web-flow · commit 7993768d86ed · 2018-12-25T23:19:53.000+08:00
diff --git a/docs/tools/Drain.md b/docs/tools/Drain.md
@@ -11,4 +11,4 @@ Drain first preprocess logs according to user-defined domain knowledge, ie. rege
 
 Read more information about Drain from the following paper:
 
-+ Pinjia He, Jieming Zhu, Zibin Zheng, and Michael R. Lyu. [Drain: An Online Log Parsing Approach with Fixed Depth Tree](http://jiemingzhu.github.io/pub/pjhe_icws2017.pdf), *IEEE International Conference on Web Services (ICWS)*, 2017.
++ Pinjia He, Jieming Zhu, Zibin Zheng, and Michael R. Lyu. [Drain: An Online Log Parsing Approach with Fixed Depth Tree](https://jiemingzhu.github.io/pub/pjhe_icws2017.pdf), *IEEE International Conference on Web Services (ICWS)*, 2017.

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`@@ -11,4 +11,4 @@ Drain first preprocess logs according to user-defined domain knowledge, ie. rege`
`11`	`11`
`12`	`12`	`Read more information about Drain from the following paper:`
`13`	`13`
`14`		`-+ Pinjia He, Jieming Zhu, Zibin Zheng, and Michael R. Lyu. [Drain: An Online Log Parsing Approach with Fixed Depth Tree](http://jiemingzhu.github.io/pub/pjhe_icws2017.pdf), IEEE International Conference on Web Services (ICWS), 2017.`
	`14`	`++ Pinjia He, Jieming Zhu, Zibin Zheng, and Michael R. Lyu. [Drain: An Online Log Parsing Approach with Fixed Depth Tree](https://jiemingzhu.github.io/pub/pjhe_icws2017.pdf), IEEE International Conference on Web Services (ICWS), 2017.`