source https://data.bnf.fr/fr/13403482/hubert_cleu/
source https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjFlYL4jrj8AhXjWaQEHetvCTsQFnoECCcQAQ&url=https%3A%2F%2Fexcerpts.numilog.com%2Fbooks%2F9782402234733.pdf&usg=AOvVaw35-Y4qzaxRvGewlsBsQvbe