his three sons nikola, fyodor and simon joined him in the business. tereshchenko's right-hand has always been his son nikola. at his thirty, he was elected as a mayor. it was him, who came up with an effective way, which gave a powerful impact to his father's business: a trade credit. he offered a good price to product manufacturers, who came to sell to the local fair, but with the condition of deferred payment until the return of the convoy. this made it possible to increase its turnover tenfold. however, such transactions require, as a condition, and the key to success, its inviolability of the word. and since a father and a son did never break their word, the surname tereshchenko became known, throughout the whole russian empire, as a synonym of "guarantor" for sellers and buyers.