(narrated by al-Bukhaari, 3047; Muslim, 819)
The word translated as "styles" is ahruf, meaning seven ways or variants. Some of these ahruf remain with us in the ten authentic qira'aat and some have been lost. There is no hadeeth describing what the seven ahruf are, so we rely on what the scholars have classified as authentic through verified chains and which follow the writing to the large degree and Arabic grammar rules.