Looking for information on Old Hewlett Packard Machines

Does anyone have information on how to get initial sale date for old Hewlett Packard computers? The current system that HP has doesn?t cover old computers from the early 1990s. I am trying to find date of sale for the systems below, and if possible, the country in which they were originally registered: ? Hewlett Packard Series 9000 712/60 (Model Number A4024A), Base Model Number A2615A, Serial Number: 6420A50415 ? Hewlett Packard Series 9000 712/60 (Model Number A2854A), Base Model Number A2615A, Serial Number: 6406A50027 ? Hewlett Packard Series 9000 712/60 (Model Number A4023A), Base Model Number A2615A, Serial Number: 6428A50358 ? Hewlett Packard Series 9000 A2051-66521 HP 9000 E35 64Mhz CPU, Serial Number: 40110293VF Is there a database for old HP computers that someone can direct me to find out information on these? Thanks!