→ skos:altLabel → "X-Factor"@en, "X-Element"@en
→ skos:prefLabel → "Икс-элемент"@ru, "X-Component"@en
→ od:SouchkovDefinition → "An unknown entity that must provide a specific change in a technical system (e.g., change in its components, parameters, physical states, chemical composition, etc.) that should be incorporated into the system in order to solve a problem."@en