I know this isn't what you mean by "studied," but here's a NASA produced video mockup of manned blimps over Venus: https://youtu.be/0az7DEwG68A https://youtu.be

I know this isn't what you mean by "studied," but here's a NASA produced video mockup of manned blimps over Venus: https://youtu.be/0az7DEwG68A https://youtu.be/0az7DEwG68A