1 

     2 @manual{isa-imp,

     3   author	= {Makarius Wenzel},

     4   title		= {The {Isabelle/Isar} Implementation},

     5   institution	= {Technische Universit\"at M\"unchen},

     6   note          = {\url{http://isabelle.in.tum.de/doc/implementation.pdf}}}