is a strength of a documentary to disregard available bias , especially 
(ROOT (S (VP (VBZ is) (NP (NP (DT a) (NN strength)) (PP (IN of) (NP (DT a) (NN documentary)))) (S (VP (TO to) (VP (VB disregard) (NP (JJ available) (NN bias))))) (, ,) (ADVP (RB especially)))))
(ROOT (S (VP (VBZ ) (NP (NP (DT ) (NN )) (PP (IN ) (NP (DT ) (NN )))) (S (VP (TO ) (VP (VB ) (NP (JJ ) (NN ))))) (, ) (ADVP (RB )))))