Cooper, Peter (2009). Beginning Ruby: From Novice to Professional. Beginning from Novice to Professional (2nd ed.). Berkeley: APress. p. 101. ISBN1-4302-2363-4. To a lesser extent, Python, LISP, Eiffel, Ada, and C++ have also influenced Ruby.
Bini, Ola (2007). Practical JRuby on Rails Web 2.0 Projects: Bringing Ruby on Rails to Java. Berkeley: APress. p. 3. ISBN1-59059-881-4. It draws primarily on features from Perl, Smalltalk, Python, Lisp, Dylan, and CLU.
Bini, Ola. "Ioke". Ioke.org. Retrieved 2011-07-21. inspired by Io, Smalltalk, Lisp and Ruby
↑Lattner, Chris (2014-06-03). "Chris Lattner's Homepage". Chris Lattner. Retrieved 2014-06-03. The Swift language is the product of tireless effort from a team of language experts, documentation gurus, compiler optimization ninjas, and an incredibly important internal dogfooding group who provided feedback to help refine and battle-test ideas. Of course, it also greatly benefited from the experiences hard-won by many other languages in the field, drawing ideas from Objective-C, Rust, Haskell, Ruby, Python, C#, CLU, and far too many others to list.