\begin{tikzpicture} \node[label={below:Médecin}] (user) { \includegraphics[width=1.33cm]{icons/doctor} }; \node[system, right=of user] (system) { Système de\\recherche }; \node[agent, right=of system] (kb) { Bases de\\connaissances }; \draw[link] ([yshift=5pt]user.east) -- node[above=5pt, link label] {signes et\\symptômes} ([yshift=5pt]system.west); \draw[link] ([yshift=-5pt]system.west) -- node[below=5pt, link label] {maladies\\associées} ([yshift=-5pt]user.east); \draw[link] ([yshift=5pt]system.east) -- node[above=5pt, link label] {requêtes} ([yshift=5pt]kb.west); \draw[link] ([yshift=-5pt]kb.west) -- node[below=5pt, link label] {connaissances} ([yshift=-5pt]system.east); \end{tikzpicture}