Webster L. Johnson MD » Member Directory Go back to directory. Add to Address Book. Webster L. Johnson, MD Gastrointestinal Specialists, AMC Work 2400 Hospital Drive, Suite 380 Bossier City LA 71111 work Work Phone: (318) 631-9121work Work Fax: (318) 549-0240workfax Website: www.gis.md Categories: Uncategorized Updated 6 years ago.