text: /// \file   countries.cpp
  ///
  /// \brief
  ///
  /// \authors    Maarten P. Scholl
  /// \date       2018-04-27
  /// \copyright  Copyright 2017-2019 The Institute for New Economic Thinking,
  ///             Oxford Martin School, University of Oxford
  ///
  ///             Licensed under the Apache License, Version 2.0 (the "License");
  ///             you may not use this file except in compliance with the License.
  ///             You may obtain a copy of the License at
  ///
  ///                 http://www.apache.org/licenses/LICENSE-2.0
  ///
  ///             Unless required by applicable law or agreed to in writing,
  ///             software distributed under the License is distributed on an "AS
  ///             IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
  ///             express or implied. See the License for the specific language
  ///             governing permissions and limitations under the License.
  ///
  ///             You may obtain instructions to fulfill the attribution
  ///             requirements in CITATION.cff
  ///
  