i have investigated many cases involving poltergeists and the article makes many good points.i have to disagree with one of them though.an"agent"can not cause a poltergeist to appear simply by being in a stressful state of mind.poltergeists search for this type of negativity and zero in on that subject.the entity then uses the agent to do what it wants to. there is also no set length of time for a poltergeist to stay in one location.if the agent stays the way they were when the poltergeist takes over,then this can last for years,but it is very,very rare.this is a great article and thanks for sharing it with us.