The 2005 film is a stylish action-comedy that centers on John (Brad Pitt) and Jane Smith (Angelina Jolie), a bored suburban couple who discover they are both secret assassins working for rival agencies. Critical Review

But what does "index of" actually mean? Why do tech-savvy users append this to their searches? And more importantly, is it safe, legal, and effective?

$$ \textbfInfluence Coefficient = \frac\textbfNumber of References\textbfTotal Number of Films \times 100 $$