remove pdfs, normalize readme format [fix PR#540]

distributed-file-systems/README.md

@@ -1,8 +1,13 @@
 # Distributed File Systems
 
-- [Sun NFS](http://www.cs.ucf.edu/~eurip/papers/sandbergnfs.pdf)
-- [Google (GFS)](https://static.googleusercontent.com/media/research.google.com/en//archive/gfs-sosp2003.pdf)
-- [Hadoop (HDFS)](https://storageconference.us/2010/Papers/MSST/Shvachko.pdf)
-- [Ceph](https://www.ssrc.ucsc.edu/Papers/weil-osdi06.pdf)
-- [Coda](http://www.coda.cs.cmu.edu/ljpaper/lj.html)
-- [Frangipani](https://pdos.csail.mit.edu/6.824/papers/thekkath-frangipani.pdf)
+* [Sun NFS](http://www.cs.ucf.edu/~eurip/papers/sandbergnfs.pdf)
+
+* [Google (GFS)](https://static.googleusercontent.com/media/research.google.com/en//archive/gfs-sosp2003.pdf)
+
+* [Hadoop (HDFS)](https://storageconference.us/2010/Papers/MSST/Shvachko.pdf)
+
+* [Ceph](https://www.ssrc.ucsc.edu/Papers/weil-osdi06.pdf)
+
+* [Coda](http://www.coda.cs.cmu.edu/ljpaper/lj.html)
+
+* [Frangipani](https://pdos.csail.mit.edu/6.824/papers/thekkath-frangipani.pdf)

languages/C++/README.md

@@ -1,3 +1,3 @@
 # C++
 
-[Why C++ is not just an Object-Oriented Programming Language-Original](http://www.stroustrup.com/oopsla.pdf)
+* [Why C++ is not just an Object-Oriented Programming Language-Original](http://www.stroustrup.com/oopsla.pdf)

languages/C/README.md

@@ -1,2 +1,3 @@
 # C
-[The Development of the C Language-Original](https://heim.ifi.uio.no/inf2270/programmer/historien-om-C.pdf)
+
+* [The Development of the C Language-Original](https://heim.ifi.uio.no/inf2270/programmer/historien-om-C.pdf)

languages/Go/README.md

@@ -1,3 +1,3 @@
 # Go
 
-[Go Lang Original Paper](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.138.6297&rep=rep1&type=pdf)
+* [Go Lang Original Paper](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.138.6297&rep=rep1&type=pdf)

languages/Java/README.md

@@ -1,5 +1,5 @@
 # Java
 
-[Java Original Paper](https://pdfs.semanticscholar.org/ee07/8894734c70589cb9653e2169a4342ae02355.pdf)
+* [Java Original Paper](https://pdfs.semanticscholar.org/ee07/8894734c70589cb9653e2169a4342ae02355.pdf)
 
-[Java Whitepaper from Strastroup website](http://www.stroustrup.com/1995_Java_whitepaper.pdf)
+* [Java Whitepaper](http://www.stroustrup.com/1995_Java_whitepaper.pdf)

search-engines/README.md

@@ -1,4 +1,7 @@
 # Search Engines Original Papers
-- [Google](http://infolab.stanford.edu/pub/papers/google.pdf)
-- [Bing](https://arxiv.org/pdf/1802.04914.pdf)
-- [Yahoo](https://www.kdd.org/kdd2016/papers/files/adf0361-yinA.pdf)
+
+* [Google](http://infolab.stanford.edu/pub/papers/google.pdf)
+
+* [Bing](https://arxiv.org/pdf/1802.04914.pdf)
+
+* [Yahoo](https://www.kdd.org/kdd2016/papers/files/adf0361-yinA.pdf)