Jauniaux, E., Zucker, M., Meuris, S., Verhest, A., Wilkin, P., & Hustin, J. (1988). Chorangiocarcinoma - An Unusual Tumor of the Placenta - the Missing Link. Placenta, 9(6), 607-613. https://doi.org/10.1016/0143-4004(88)90004-5 (Original work published 1988)