A Turing-complete basis of operators is:
- \(If\quad\triangleright\quad f\)
- \(Kfg \quad\triangleright\quad f\)
- \(Sfgx \quad\triangleright\quad fx(gx)\)
- Felice Cardone, J. Roger Hindley. . "Lambda-calculus and Combinators in the 20th Century". In Logic from Russell to Church, edited by Dov M. Gabbay and John Woods, 5:723–817. Handbook of the History of Logic. Elsevier. DOI.