Oportet eum, qui ex his vult lucrari pecuniam, esse expertum quae eorum sint maxime cara, et in quibus locis; quia alia istorum in aliis regionibus abundant; ut scilicet emat in loco ubi abundant, et vendat in loco ubi sunt cara.
"It's needful for one who wishes to increase wealth, to be knowledgeable of those things that are most precious, and in what place; because some things abound in some regions and others in others. Thus it follows that he must buy in the place where they abound, and sell in the place where they are precious."
Sententia libri Politicorum lib. 1 lect. 9 n. 3