Akademik

Услуга за услугу
Any favo(u)r or help you receive should be repaid. See Долг платежом красен (Д), За добро добром и платят (3), Ты - мне, я - тебе (T)
Cf: One good deed deserves another (Am.). One good turn deserves another (Am., Br.). Scratch my breech and I'll claw your elbow (Am.). /You/ roll my log, and I'll roll yours (Br.). You scratch my back, and I'll scratch yours (Am., Br.)

Русско-английский словарь пословиц и поговорок. . 2013.