How to use decades in this sentence?

Question

I want to say ongoing research on matter X using the word decades. The research started from the date of discovery of matter x in 1982 onwards. This should be an opening statement of an academic abstract.

My sentence is:

Over three decades following its discovery, matter x has been a focus of ongoing research worldwide.

or

For over three decades following its discovery, matter x has been a focus of ongoing research worldwide.

or

For more than three decades following its discovery, matter x has been a focus of ongoing research worldwide.

which one is more correct?

Answer 1

Over the three decades following its discovery...

This is somewhere a determiner is necessary.

Answer 2

"For more than three decades..." or "For over three decades..." is appropriate. It's a prepositional phrase, so "for" is necessary.