I am doing some research and need to know the first software (or even an article that talks about this concept) that allowed users to create some sort of geofence and would send out alerts of some kind (e.g. email, pager notification, sound alert) when the object or thing being tracked either entered or left the geofence.
I need either a book or article that talks about this idea or a reference to software that actually did this. The reference needs to be from before 1998.
This info is very valuable for my research, I am willing to provide a cash reward for references that can be validated. $250 per unique reference. If more than one person reports the same reference I will pay only the first person who reports the reference.
I know that this technology was used before 1998 by military, animal tracking etc, I just need documented references.