anchor.diff:  usage, with a number of papers describing the formalism:
   
   - _Metamathematical Investigations of a Calculus of Constructions_, by
  -  Thierry Coquand (INRIA Research Report N°1088, Sept. 1989, published
  -  in Logic and Computer Science, ed. P.G. Odifreddi, Academic Press,
  -  1990)
  +  Thierry Coquand <<C90>>,
   - _Inductive definitions in the Calculus of Constructions_, by
  -   Christine Paulin-Mohring,
  +   Christine Paulin-Mohrin,
   - _Extracting Fω's programs from proofs in the Calculus of
  -  Constructions_, by Christine Paulin-Mohring (published in POPL'89)
  -- _The Constructive Engine_, by Gérard Huet
  +  Constructions_, by Christine Paulin-Mohring <<P89>>,
  +- _The Constructive Engine_, by Gérard Huet <<H89>>,
   
   as well as a number of user guides:
   
  
positive.code: ====
  September 2015 +
  Thierry Coquand, Gérard Huet and Christine Paulin-Mohring.
  ====
negative.code: _Induction and Recursion in the Theory of Constructions_ was presented
  as an invited paper at the Joint Conference on Theory and Practice of
  Software Development TAPSOFT’87 at Pise in March 1987, and published
  as __Induction Principles Formalized in the Calculus of
  Constructions__ <<H88>>.
  
  Version 3
  ---------
  