Anatolii Kmetiuk, Mastering Functional Programming: Learn how functional programming can help you in deploying web servers and working with databases in a declarative and pure way

Atul S. Khot, Scala Functional Programming Patterns: Grok and perform effective functional programming in Scala

Ivan Nikolov, Scala Design Patterns - Second Edition: Learn how to write efficient, clean, and reusable code with Scala