Books

Reactive Programming in Kotlin
Packt: https://www.packtpub.com/application-development/reactive-programming-kotlin
Amazon: https://www.amazon.com/Reactive-Programming-Kotlin-non-blocking-Reactor-Kotlin-dp-1788473027/dp/1788473027/

Functional Kotlin
Packt: https://www.packtpub.com/application-development/functional-kotlin
Amazon: https://www.amazon.com/Functional-Kotlin-Extend-implement-techniques/dp/1788476484/

Hands-On Data Structures and Algorithms with Kotlin
Packt: https://www.packtpub.com/application-development/hands-data-structures-and-algorithms-kotlin
Amazon: https://www.amazon.com/Hands-Data-Structures-Algorithms-Kotlin-ebook/dp/B07DTG2629/