F. R. Cabar, D. R. K. Teshima, P. P. Pereira, L. Antonangelo, R. Schultz, and R. P. Francisco, “ Serum concentration of vascular endothelial growth factor and depth of trophoblastic invasion in ampullary ectopic pregnancy ”, Clinics, vol. 71, no. 12, pp. 699–702, Dec. 2016, doi: 10.6061/clinics/2016(12)04.