Jonathan Moreno, PhD, wrote in his 1995 book Arguing Euthanasia: The Controversy Over Mercy Killing, Assisted Suicide, and the "Right to Die":
“Strictly speaking, the term ‘euthanasia’ refers to actions or omissions that result in the death of a person who is already gravely ill. Techniques of active euthanasia range from gunfire to lethal injection, while passive euthanasia can be achieved by failing to treat a pneumonia or by witholding or withdrawing ventilatory support.”
1995