Biliary Stones

• Hospital Universitari Trias i Pujol — Badalona, Barcelona, Spain
• IDIBELL, Hospital Universitari de Bellvitge. — Barcelona, Spain
• Hospital del Mar — Barcelona, Spain
• Hospital Universitari Vall d'Hebron — Barcelona, Spain

• Endoscopy Centre, Prince of Wales Hospital — Hong Kong, NT

• Stanford University Medical Center — Stanford, California, United States
• University of Colorado Hospital, Denver — Aurora, Colorado, United States
• Ochsner Clinic Foundation — New Orleans, Louisiana, United States
• Ertan Digestive Disease Center - University of Texas Health Science Center — Houston, Texas, United States

• Faculty of Medicine-Assiut University -Assiut-Egypt — Asyut, Asyut Governorate, Egypt

• Stanford University School of Medicine — Stanford, California, United States

Not specified

• Johns Hopkins Hospital — Baltimore, Maryland, United States