TITLE: References about Hasse diagrams of root systems
QUESTION [6 upvotes]: This is to ask about references of Hasse diagrams of irreducible root systems. I found here and there nice pictures of root systems of type $E$. I would like to ask for Hasse diagrams of classical root systems ($A_n, B_n, C_n, D_n$).
Thanks in advance.

REPLY [4 votes]: I put a LaTeX package up on CTAN today to draw the Hasse diagrams of all root systems, following Ringel's pictures. Code is as simple as
\documentclass{amsart}
\usepackage{lie-hasse}
\begin{document}
\hasseDiagrams{A4;B5}
\hasseDiagrams{F4;G2}
\end{document}

to display