The unflattering sonnet Emelia is quoting ("My mistress'eyes are nothing like the sun") is Shakespeare's sonnet number 130.
The sonnet Lord Southampton is quoting ("A woman's face with nature's own hand painted") is Shakespeare's sonnet number 20.
In the final scene, Anne predicts that sonnet 18 ("Shall I compare thee to a summer's day?") will become quite popular and that sonnet 116 ("Let me not to the marriage of true minds admit impediments.") will be a big hit at weddings.
Robert Greene quotes sonnets 135 ("Wilt thou, whose will is large and spacious") and 129 ("Th'expense of spirit in a waste of shame"), rather than 126 as said on screen, as evidence during the dungeon scene.
The title is taken from Shakespeare's Sonnet number 116.