When Madeline, Roderick, and Pym are talking in the boardroom, Madeline quotes the Poe short story "Eleanore" when she says, "Men have called me mad; but the question is not yet settled, whether madness is or is not the loftiest intelligence." This is the second quote from this story to appear in this episode.
Mike Flanagan directed this along with Gerald's Game, which can be seen on the TV while in the hospital at the 35:00 minute mark. Both feature Carla Gugino, Bruce Greenwood, Henry Thomas and Kate Siegel.
At 16:41, Roderick tells his granddaughter "All that we see or seem is a dream within a dream." This quote is taken directly from the Poe poem "Dream Within a Dream."
Near 16:26, Roderick says "As those who dream by day are cognizant of many things, which escape those who dream only by night." This is a quote from Poe's tale "Eleanora."
Verna's drivers license says her name is Pamela Clemm, address is 1849 Reynolds Street, DOB is 01/19/1983, mostly referencing Edgar Allan Poe. Clemm is the maiden name of his wife, Virginia. Poe died in 1849 and allegedly repeatedly called out the name "Reynolds" the night he was dying. His birthday was January 19, 1809.