Manusmriti
पञ्चरात्रे पञ्चरात्रे पक्षे पक्षेऽथ वा गते । कुर्वीत चैषां प्रत्यक्षमर्घसंस्थापनं नृपः ॥ ४०२ ॥
Once in five nights, or at the close of each fortnight, let the king publicly settle the prices for the (merchants).
english translation
paJcarAtre paJcarAtre pakSe pakSe'tha vA gate । kurvIta caiSAM pratyakSamarghasaMsthApanaM nRpaH ॥ 402 ॥
hk transliteration by Sanscript