1. Percutaneous needle biopsy. A new technique;Lindgren, P.G.;Acta Radio[Diagn],1982
2. Villous tumours of the duodenum;Spira, I.A.; Wolff, W.I.;Amj Gastroenterol,1977
3. Benign neoplasms of the extrahepatic biliary ducts;Burhans, R.; Myers, R.T.;Am Surg,1971
4. Polypoid epithelial tumours of the bile ducts;Cattell, A.H.;N EnglJ Med
5. Tumours of the gallbladder and extrahepatic bile ducts. Atlas of Tumor Pathology;Edmondson, H.A.,1967