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Diakses pada 29 Agustus 2020Medical News Today. https://www.medicalnewstoday.com/articles/322319#:~:text=Share%20on%20Pinterest%20Bellybutton%20pain,longer%20fits%20inside%20the%20pelvis.
Diakses pada 29 Agustus 2020What to Expect. https://www.whattoexpect.com/pregnancy/symptoms-and-solutions/protruding-navel.aspx
Diakses pada 29 Agustus 2020