Update README.md

Author: mnievesc

README.md

@@ -15,7 +15,7 @@ echo "I am a command, please type or copy-paste me into your terminal"
 ```
 Comments will be noted by this sign `#`. You do not need to copy these into your terminal, they are just here to give additional information on what the commands are doing.
 
-We will be working with example files in .bed format I downloaded and modified from the UCSC genome browser (https://genome.ucsc.edu/). I picked the .bed format because the data is organized in tab-delimited format which is exactly the type of data that awk excels at working with. For more on the .bed format see: https://genome.ucsc.edu/FAQ/FAQformat.html#format1. I also want to mention that the content and structure of this tutorial is largely based on the great chapter **Unix Data Tools** in *Buffalo V (2015). Bioinformatics Data Skills. O'Reilly Media*.
+We will be working with example files in .bed format I downloaded and modified from the UCSC genome browser (https://genome.ucsc.edu/). I picked the .bed format because the data is organized in tab-delimited format which is exactly the type of data that awk excels at working with. For more on the .bed format see: https://genome.ucsc.edu/FAQ/FAQformat.html#format1. I also want to mention that the content and structure of this tutorial is largely based on the great chapter **Unix Data Tools** in *Buffalo V (2015). Bioinformatics Data Skills. California: O'Reilly Media* http://shop.oreilly.com/product/0636920030157.do. 
 
 
 ## So let's get started!