We are grateful to these people for their comments, help, or
suggestions.

Akim Demaille
Andreas Tollkötter
Anton Pirogov
Ayrat Khalimov
Caroline Lemieux
Christian Dax
Christopher Ziegler
David Müller
Ernesto Posse
Étienne Renault
Fabrice Kordon
Felix Klaedtke
Florian Perlié-Long
František Blahoudek
Gerard J. Holzmann
Heikki Tauriainen
Henrich Lauko
Jan Strejček
Jean-Michel Couvreur
Jean-Michel Ilié
Jeroen Meijer
Joachim Klein
Juraj Major
Kristin Y. Rozier
Martin Dieguez Lodeiro
Matthias Heizmann
Maxime Bouton
Michael Tautschnig
Michael Weber
Mikuláš Klokočka
Ming-Hsien Tsai
Nikos Gorogiannis
Paul Guénézan
Reuben Rowe
Rüdiger Ehlers
Silien Hong
Simon Jantsch
Shufang Zhu
Sonali Dutta
Tobias Meggendorfer.
Tomáš Babiak
Valentin Iovene
Vitus Lam
Yann Thierry-Mieg
Yuri Victorovich