zener di̇ode

Given a zener of 4.7V with a knee current of 1mA and a maximum power dissipation of 1W . Design a regulated power supply to deliver a load current ranging from 0 to 50 mA. Given an AC Supply of 230 Vrms , 50 Hz . Design an auxiliary Circuit which gives an output ranging from 8 to 8.4V i saw...

Hi, I found an oscillator circuit and there are two parts not identified. IC1 and IC2. The symbol looks to be Zener diodes but There is no value .Would anyone have an idea what they could be? Please see The schematic ,bottom left corner Best regards to all, Stay safe.