I need to attach new sheet rock to the ceiling.

It was removed since there were some leaks and stains which has since been
repaired. At first I thought the sheet rock were attached to the ceiling
joist, but after I had them removed, I noticed they attached 1x3 fir furring
strips perpendicular to the joist spaced 16" apart, the fiber glass
insulation were then placed between two joists, resting on the furring
strips.

Now I need to attached new sheet rock and wonder what is the best way to
fasten it. Should I use screws, nails, or staples? Is it the same rule as
walls - once every eight inches?

Thanks,

MC