"early studies" is correct and usable in written English.
For example, "Early studies of the Chernobyl disaster showed the devastating effects of the nuclear disaster."
Early studies of bits of DNA also supported this idea.
The early studies made the effect look very robust".
He concentrated mainly on the clarinet in his early studies.
"The early studies have found positive impact on young children, especially in certain subgroups.
In early studies, it was shown to decrease malaria cases about 25percentt.
"A lot of Vincent's early studies were left in Breda by his mother.
Some early studies indicated what was really happening, but were widely dismissed.
The gift includes early studies from nature, still lifes and mythological images.
Some early studies showed a small increase in violent deaths, including suicides.
Dr. Close's efforts also played an indirect role in early studies of H.I.V. a decade later.
His early studies in intellectual history continue to be widely influential.
