kael 17 Oct 2023 in Public ipc classification patents wikipedia:en=Patent_classification wikipedia:en=International_Patent_Classification wikipedia:en=Strasbourg_Agreement_Concerning_the_International_Patent_Classification
kael 17 Oct 2023 in Public ipc classification patents wikipedia:en=Patent_classification wikipedia:en=International_Patent_Classification wikipedia:en=Strasbourg_Agreement_Concerning_the_International_Patent_Classification