1. A method of generating reference patterns able to represent hierarchized data, the hierarchized data being structured in accordance with a schema, the schema defining the structure of the hierarchized data, and the hierarchized data being organized in a plurality of items, the method comprising a step of providing a computer microprocessor configured for carrying out the steps of: obtaining the schema defining the structure of the hierarchized data; extracting primary structural patterns from the schema defining the structure of the hierarchized data, each of the primary structural patterns representing a set of structural information; creating a list of instances for at least one extracted primary structural pattern, each instance associating items of the plurality of items with a corresponding primary structural pattern; grouping instances of one and a same primary structural pattern into one or several groups of instances according to a predetermined similarity criterion applied on items of distinct instances; extracting at least one piece of structural information common to each instance of one of the groups of instances, for each of the groups of instances, and generating one reference pattern from the primary structural pattern associated with the one group of instances, the reference pattern including the extracted at least one piece of structural information, wherein the steps of extracting at least one piece of structural information and generating one reference pattern comprise the following sub-steps for at least one group of instances: extracting the structural information and content information common to a high number of instances in the group; and generating a reference pattern containing the structural information and the common content information extracted, the reference pattern being able to represent some of the structural information and the content information of items in the group, wherein, when the number of instances in the group of instances is below a predetermined threshold, the group of instances is assembled with another group of instances, and wherein the group of instances is assembled with the group of instances closest to the group of instances with respect to a distance measurement.