Arthashastra
धान्य रस लोह पण्याः शकट व्यवहारिणश् च त्रिंशत् कराः ॥
Those that trade in grains, liquids, metals (loha), and deal with carts shall pay 30 karas.
english translation
dhAnya rasa loha paNyAH zakaTa vyavahAriNaz ca triMzat karAH ॥
hk transliteration by Sanscript