Reference

For an overview of pattern matching in Scala, there is no better reference than Programming in Scala, by Martin Odersky, Bill Venners, and Lex Spoon. An online version of the first edition is available at: https://www.artima.com/pins1ed/case-classes-and-pattern-matching.html.

Daniel Westheide's blog covers slightly more advanced Scala constructs, and is a very useful read: http://danielwestheide.com/blog/2012/11/21/the-neophytes-guide-to-scala-part-1-extractors.html.