I. Introduction
Nowadays, software can be licensed in many ways by fulfilling what is called a metric. A metric defines a way to calculate the number of licenses required for software, so it can be licensed with licenses under metric A or licenses under metric B. The price of licenses depends on the metric used. The metrics of software licenses are defined contractually either by the general conditions of sale found on the publisher's website or by a contract between the buyer and the publisher. The general terms and conditions of sale available online can be modified at any time, but a license purchased prior to a change in the legal text must follow the old version of the metric definition, so it is necessary to have a continuous monitoring of these metrics and the ability to identify and retrieve the legal documents of each license in the computer park.