Detection of human papilloma virus-E6/E7 proteins of high-risk human papilloma virus in saliva and lesional tissue of oral squamous cell carcinoma patients using nested multiplex polymerase chain reaction: A comparative study. - Grewal RK; Sircar K; Bhat KG; Grewal DS; Tyagi KK; David S (Journal of oral and maxillofacial pathology : JOMFP, 2018)