This notch filter was found in National Semiconductor documentation from the 1980s. Operational amplifiers are from that era. The configuration can be adapted to use modern operational amplifiers.
Found on Popular Electronics this circuit has variations found throughout this site and section....
Found in an Electronics Now from the 1980s, this circuit uses some components that are still...
High Current Through Hole Inductors for Vishay's 5A Series IHXL-2000VZ-5A Series Power Supply are...