Ratan, S.K., Aggarwal, S.K., Khurana, N.A., Dhua, A., Mufti, G.N. and Deshpandey, V. 2011. Retroperitoneal fetus-in-fetu: another supportive evidence for twinning theory. Teratology Studies. 1, 1 (Nov. 2011), e2. DOI:https://doi.org/10.4081/ts.2011.e2.