What are the Four types of unemployment and how do they changeovervthe business cycle?

What are the Four types of unemployment and how do they changeovervthe business cycle?
The four types of unemployment are...
1) seasonal- for example an immigrant comes to pick strawberries can only have this job in the months that strawberries grow.
2) cyclical- or aka laid off
3) Frictional- when a person who has lost a job can easily find another similar to it. For example, suppose a nurse is out of work, she can go anywhere in the country and get a similar job, if not the same one.
4) Structural- this is the most serious type of unemployment, aka the "discouraged worker" when a out of work person gives up on finding a job.