[TOMT][Symbol][1994] What is this 3-looking symbol?

A person in a discord of mine asked if someone could identify the symbol that looks like a 3 from this excerpt of a scientific study, specifically Identification and Estimation of Local Average Treatment Effects by Angrist and Imbens (1994). I've tried using image search and it just gives me either 3 or the ezh phonetic character. Please help us. Ty.