Some studies collect data from a small number of sites but have no other features in common with case studies and offer none of their advantages.
Some studies use a small number of sites, that are not similar to case studies.
The studies that collect data from a small number of sites give the best information.
The bull is chasing 2 rodeo riders.
A mermaid makes love to Tom Hanks.
The man is standing.
Someone is cooking.
One chap was rather obese to say the least.
I am not a college student.