"http://www-formal.stanford.edu/jmc/progress/notes.html#tractor http://www-formal.stanford.edu/jmc/progress/notes.html#tract..." Seems like the link is wrong...

"http://www-formal.stanford.edu/jmc/progress/notes.html#tractor http://www-formal.stanford.edu/jmc/progress/notes.html#tract..." Seems like the link is wrong... it only works when you replaced that '-' with a '.'. Odd that it already has 4 points but no comments regardless of that....