Here are some more links which may be of interest to existing or prospective ZSH users.

• The main ZSH archive site.
• Zsh lovers, a project that collects tips tricks and examples.
• awesome-zsh-plugins Collection of links to zsh frameworks, plugins and themes.
• An introduction by Adam Spiers to advanced interactive use of shells, particularly ZSH. Adam's ZSH page is also useful if somewhat dated.

• Linux Magazine — Wilder Wildcards by Jerry Peek, March 2004
• Linux Magazine — Catching Some ZZZs by Jerry Peek, February 2004
• Linux Magazine — Writing Zsh Completion Functions by John Beppu, July 2002
• Linux Magazine — Writing Scripts for Zsh by John Beppu, June 2002
• Linux Magazine — Making the Transition to Zsh by John Beppu, May 2002

• From Bash to Z Shell: Conquering the Command Line. Published November 2004.
  • Authors' Page
• Zsh: Die magische Shell. Published 2008; in German

• Debian bug reports for zsh
• ZSH project page on source forge
• Single UNIX specification — contents and shell command language