Source: http://www.methodes-naturelles.fr/les_methodes_naturelles/la-methode-dauto-observation/apres-une-naissance-apres-la-pillule-avant-la-menopause-cycles-irreguliers/les-methodes-naturelles-en-periode-de-premenopause/linstallation-de-la-menopause-dr-michele-guy-oct-2009.pdf