Source: https://le-groupe-laposte.cdn.prismic.io/le-groupe-laposte%2F3fedab00-0f44-402e-bdbc-623c08e89ae6_le%2Bgroupe%2Bla%2Bposte%2B-comptes%2Bconsolid%C3%A9s%2B31.12.2017%2B.pdf