\documentclass[a4paper, 10pt]{article}% language\usepackage[italian]{babel}% figures\usepackage{graphicx}% math packages\usepackage{amsmath}\usepackage{cancel}% circuits\usepackage{pst-circ}\title{Essenza di Elettronica}\author{Naoki Pross}\begin{document}\maketitle\include{tex/opamp}\end{document}