minor modifiations to the Intro and FirstSteps chapters
@manual{isa-imp, author = {Makarius Wenzel}, title = {The {Isabelle/Isar} Implementation}, institution = {Technische Universit\"at M\"unchen}, note = {\url{http://isabelle.in.tum.de/doc/implementation.pdf}}}@Book{isa-tutorial, author = {Tobias Nipkow and Lawrence C. Paulson and Markus Wenzel}, title = {Isabelle/HOL: A Proof Assistant for Higher-Order Logic}, publisher = {Springer}, year = 2002, note = {LNCS Tutorial 2283}}@book{paulson-ml2, author = {Lawrence C. Paulson}, title = {{ML} for the Working Programmer}, year = 1996, edition = {2nd}, publisher = {Cambridge University Press}}