Armstrong, Joe. Programming Erlang: software for a concurrent world. Pragmatic Bookshelf, 2013.
Thomas, Dave. Programming Elixir 1.6: Functional> Concurrent> Pragmatic> Fun. Pragmatic Programmers, 2018.
Almeida, Ulisses. Learn Functional Programming with Elixir: New Foundations for a New World. Pragmatic Programmers, 2018.
Marx, Ben; Valim, José; Tate, Bruce. Adopting Elixir: From Concept to Production. Pragmatic Programmers, 2018.
Davi, Tiago. Elixir: Do zero à concorrência. Casa do Código, 2017.
Tate, Bruce. Seven Languages in Seven Weeks: A Pragmatic Guide to Learning Programming Languages. Pragmatic Programmers, 2010. The book that inspired José Valim to create Elixir. It includes a chapter on Erlang.
Tate, Bruce; Daoud, Fred; Moffitt, Jack; Dees, Ian. Seven More Languages in Seven Weeks:
Languages That Are Shaping the Future. Pragmatic Programmers, 2014. It includes a chapter on Elixir.
Research papers on concurrent functional programming.