http://books.google.com/books?id=V11yhBL4ttcC&pg=PA18&dq=hart+%22open+texture%22+vehicles&hl=en&ei=dYhsTcLyGYOosAOEzeCwBQ&sa=X&oi=book_result&ct=result&resnum=2&ved=0CDQQ6AEwAQ#v=onepage&q=hart%20%22open%20texture%22%20vehicles&f=false