oṃ āḥ hūṃ
唵 阿 吽
ॐ आः हूँ
A short and sweet article at the Samye Institute: Oṃ āḥ hūṃ: The Three Syllables
Another good article at VisibleMantra.Org: The Seed Syllable āḥ – and oṃ āḥ hūṃ
A short and sweet article at the Samye Institute: Oṃ āḥ hūṃ: The Three Syllables
Another good article at VisibleMantra.Org: The Seed Syllable āḥ – and oṃ āḥ hūṃ