external reality external reasons external recognition external recruitment external reference external references external relations external relations and development external relationships external release external reporting external representation external requirements external research external researchers external resistance external resource external resources external review external reviewers external reviews external rewards external ring external risks external rotation external rotor external safety external sales external scientific external screw external sector external security external sensor external sensors external server external service external service provider external service providers external services external shape external shell external shock external shocks external side external sign external signal external signals external signs external site external sites external situation external size external skin external sleeve external social external software external solution external sound external source external sources external space external speaker external speakers external staff external staircase external stairs external stakeholder external stakeholders external standard external standards external stimulation external stimuli external stimulus external storage external storage device external storage devices external strategy external stress external structure external structures external studies external study external subwoofer external supplier external suppliers external supplies external supply external support external surface external surfaces external surplus external switch external symptoms external sync external system external systems external tank external tariff external team