How to get the serial number of CD, DVD and blu ray disc

Uing C# and .Net Framework, how do I get the unique serial number of a CD disc, a DVD disc and Blu-ray disc. Using two different commercial software, I get two different serial numbers for the same CDs. For example, Software 1 gives 2871-B669 and Software 2 gives 678540905 for CD 1. Software 1 gives 0E69-FCAC and Software 2 gives 241826988 for CD 2. I don't even know which is correct. A sample C# program and/or code examples would be nice. Thanks in advance.