https://123dok.net/document/zx5jm0oq-en-fr-description-of-spatial-databases-public-deliverable-d6-6-prima-collaborative-project-eu-7th-framework-programme-contract-no-212345-description-des-bases-de-donnees-spatiales-delivrable-n0-d6-6-projet-europeen-prima-7e-pcrd-contrat-n0-212345.html