Selective neck dissection for N0 and N1 oral cavity and oropharyngeal cancer: are skip metastases a real danger? - Lodder WL; Sewnaik A; den Bakker MA; Meeuwis CA; Kerrebijn JD (Clinical otolaryngology : official journal of ENT-UK ; official journal of Netherlands Society for Oto-Rhino-Laryngology & Cervico-Facial Surgery, 2008)