secondary source in a sentence

Examples

1. I retained those statements which were commented on by secondary sources.
2. The line between primary and secondary sources is not always clear.
3. There is insufficient citation of secondary sources to establish sufficient notability.
4. Note that there are no lack of god quality secondary sources.
5. There were several nontrivial mentions of the subject in secondary sources.
6. I believe this is a secondary source as has been requested.
7. There are two secondary sources provided out of four total sources.
8. So reporters are must rely on secondary sources for their information.
9. Her fate in Chinese service is not reported in secondary sources.
10. My question is : Are court opinions primary or secondary sources?