A Correspondence Between ALGOL 60 and Church's Lambda-Notation

A pair of papers that contain the first published description of the connection between -calculi and real-world programming languages:

• A Correspondence Between ALGOL 60 and Church’s Lambda-Notation: Part I
• A Correspondence Between ALGOL 60 and Church’s Lambda-Notation: Part II

See also Landin's previous paper The mechanical evaluation of expressions.