Ex-US sailor John A. Walker who spied for Soviets dies in prison hospital
John Walker - Counterintelligence - LibGuides at Naval War College
John Walker Jr. - IMDb
John Walker Jr., spy family ringleader, dies in prison at 77 - Los Angeles Times
John A. Walker Jr. dies at 77; masterminded family spy operation - Los Angeles Times
John Walker: American naval officer who formed a family spy ring that passed highly damaging secrets to the Soviet Union | The Independent | The Independent