Avete ragione. Eccolo:
`
\usepackage[italian]{babel}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{microtype}
\usepackage{geometry}
\usepackage[sf]{titlesec}
\usepackage{verbatim}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{latexsym}
%—-Bibliografia————————
\usepackage[babel]{csquotes}
\usepackage[useprefix, style=numeric]{biblatex}
\bibliography{MaterialeStartEnd/Bibliografia}
\renewcommand{\rmdefault}{ptm}
\renewcommand{\sfdefault}{ptm}
\renewcommand{\ttdefault}{ptm}
\usepackage{setspace}
\usepackage{graphicx}
\usepackage{subfig}
\usepackage{booktabs}
\usepackage{tabularx}
\usepackage[table,svgnames,dvipsnames,x11names]{xcolor}
%—————————–IMPAGINAZIONE—————————————–
\footskip=15pt \hoffset=1pt \textwidth=400pt \textheight=700pt
\setlength{\textheight}{200mm} \setlength{\textwidth}{140mm}
\setlength{\baselineskip}{20mm}
\hoffset=5mm \voffset= 10mm
\footskip= 20mm %\headsep =30mm
%——————————————————————————————
% PER I SISTEMI DI EQUAZIONI
\newenvironment{sistema}%
{\left\lbrace\begin{array}{@{}l@{}}}%
{\end{array}\right.}
\begin{document}
\include{MaterialeStartEnd/Dedica}
\pagenumbering{roman}
\include{MaterialeStartEnd/Indice}
\pagestyle{headings}
\pagenumbering{arabic}
\include{Capitoli/Capitolo1}
\include{Capitoli/Capitolo2}
\include{Capitoli/Capitolo3}
\include{MaterialeStartEnd/Conclusioni}
\addcontentsline{toc}{chapter}{\bibname}
\printbibliography
\include {MaterialeStartEnd/Ringraziamenti}
\end{document}
`