Information about magnesium

I've just been reading quite an interesting website about the effects on health of magnesium deficiency + benefits of supplementation.

I think that magnesium deficiency is implicated in my insomnia.

Somewhere on the site it says that liquid magnesium chloride is not well absorbed orally but you really need something like magnesium glycinate.

Does anybody know what the most absorbable form of magnesium is?
Tina