What are the names of the scholars who interpreted the exemption of the beard [from being grown long] by its density, even if it does not reach a fistful?

Scholars differed regarding the extent of letting the beard grow; some held that letting it grow means leaving it to lengthen without trimming, while others, among them Abu Hanifa, held that letting it grow means leaving it until it becomes dense, and that trimming it is a Sunnah, by taking what exceeds a fistful.