Gupta, P., V. Karuna, P. Singh, and N. Verma. “Signet Ring Cell Cholangiocarcinoma in a Patient Previously Operated for Cholecystectomy: Is There Any Connecting Link?”. International Journal of Research in Medical Sciences, vol. 7, no. 11, Oct. 2019, pp. 4416-21, doi:10.18203/2320-6012.ijrms20195029.