Perhaps you should try some spelling variations:
"radio / appareils der materielle / guides, manuels, etc" » "radio / appareils der materiellen / guides, manuels, etc", "radio / appareils die materielle / guides, manuels, etc", "radio / appareils das materielle / guides, manuels, etc", "radio / appareils de materielle / guides, manuels, etc", "radio / apparails de materielle / guides, manuels, etc", "radio / appareils du materielle / guides, manuels, etc"
"radio / appareils et materielle / guides, manuels, etc" » "radio / appareils et materiel / guides, manuels, etc", "radio / appareils 4 materielle / guides, manuels, etc", "radio / appareils 3 materielle / guides, manuels, etc"

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