DOF_VERSION="Unreleased"
ISABELLE_VERSION="Isabelle2019: June 2019"
ISABELLE_URL="https://isabelle.in.tum.de/website-Isabelle2019/"
DOF_ARTIFACT_URL="https://artifacts.logicalhacking.com/releases/Isabelle_DOF/Isabelle_DOF"
AFP_DATE="afp-2019-06-17"
AFP_URL="https://www.isa-afp.org/release/"$AFP_DATE".tar.gz"