\usepackage{type1cm}
\usepackage{caption}
\usepackage[utf8]{inputenc}
+\usepackage{amssymb}
\usepackage{makeidx} % allows index generation
\usepackage{graphicx} % standard LaTeX graphics tool
\usepackage{newtxtext} %
\usepackage{newtxmath} % selects Times Roman as basic font
+\usepackage{diagbox}
% see the list of further useful packages
% in the Reference Guide
\mainmatter%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\include{part}
\include{chapter1}
+\include{chapter2}
\include{references}