I. Introductory Remarks  
A. Review of Survey and Overview Papers on O-RAN  
B. The Primary Survey Gap in the Literature  
C. Goals and Contributions  

II. Ongoing Standardization Efforts and Open Source Contributions to the O-RAN Architecture  
A. Key Features and Principles of O-RAN  
B. Network Slicing  
C. O-RAN Standards and Activities  
D. O-RAN-Related Open Source Projects  
E. Open Testbeds  

III. In-Depth Analysis of O-RAN Architecture with a Particular Emphasis on Network Slicing  

IV. O-RAN NFs, Network Slicing, and SMO Deployment Options  
A. O-RAN NF Deployment Scenario  
B. Network Slicing Deployment Options in O-RAN  
C. SMO Framework Deployment Options  

V. Slicing the Underlying Infrastructure in O-RAN Architecture  
A. O-RAN Cellular Site  
B. O-RAN Cloud Platform  
C. Xhaul Transport Network  

VI. Exploring Use Cases Related to Network Slicing in O-RAN Architecture  
A. Slice Subnet Management and Provisioning Use Cases  
B. RAN Slice SLA Assurance  
C. Multi-vendor Slices  
D. NSSI Resource Allocation Optimization  

VII. Concluding Remarks and Future Outlook