ER exercise: Papers

Below is an ER model for a research group in chemistry that we're going to interpret. It is mainly concerned with keeping track of papers and the reactions they discuss.

Questions you should answer:

1. List the entity types.
2. List the relationships.
3. What's the maximum number of papers an author can write?
4. What's the minimum number of papers a paper can refer to?
5. What's the minimum number of papers a paper can be referred to by?
6. Are there any people who didn't write papers in the Author table?
7. Can we say exactly how many journals an issue can be in?
8. What's the maximum number of journals a paper can be in?
9. Can we say exactly how many journals a paper can be in?
10. What's the minimum number of papers a journal can contain?
11. What's the minimum number of authors for all the papers in one journal?
12. Does a paper have to be referred to by another paper?
13. How many tables would be needed for this database?
14. How many primary keys would be needed for this database?
15. List all the tables in which a foreign key referring to Issue appears.
16. List all the tables in which a foreign key referring to Paper appears.