https://2.bp.blogspot.com/-qIso4XHDKf4/W6NxMnFVA5I/AAAAAAAAQV0/eViUMI5_x_QwyZ374uEE26M0PmfeoC2IACLcBGAs/s1600/peredaran_darah.gif
http://file.upi.edu/Direktori/SPS/PRODI.PENDIDIKAN_IPA/195107261978032-FRANSISCA_SUDARGO/Model_Buku_IPA_SMP_%28Revisi-2007%29/02._Kelas_VIII/Bab._6-VIII_Sistem_Peredaran_Darah_Pada_Manusia_%28Sisca%29.pdf
https://www.ruangguru.com/blog/sistem-peredaran-darah