René Vestergaard James Brotherston The Mechanisation of Barendregt-Style Equational Proofs (the Residual Perspective). 2001 58 Electr. Notes Theor. Comput. Sci. 1 http://www.elsevier.nl/locate/entcs/volume58.html db/journals/tcs/entcs58.html#VestergaardB01