On page 196 of "just After Sunset" in the short story N. the OCD pateint is describing his counting problem and mentions the number 19. mentions it to be a powerful and bad number.

"Divide 3728 by two and you come out with eighteen-hundred-and-sixtyfour. 1864 adds up to nineteen, a powerful odd number. powerful and bad."-just after sunset

What N. sees in Ackermans Field could be a speaking circle. He talks about the field seeming thin, like at any moment things from other universes could come spilling out.

N. mentions the number 19 as being a "powerful odd number" "powerful and bad".

The whole story revolves around a madness surrounding "keepers" of an entity protected and held in by a circle of 8 stones. This is also the case in a couple of the Dark Tower books, although this may in fact be a "thinny" through to Todash space and an indescribable monster from this universe is trying to escape.

This is more of the number 19 reference. In the short story N. in Just After Sunset, Sheila, Dr. Johnny Bonsaint's sister, sends a letter to her and her brother's best friend growing-up. The address she gives to where she lives is 964 Lisbon Street. Add 964 up and you get 19

At the end of the short story, N., Charlie sends an email to Chrissy about having to leave town for a bit to attend to a matter back home in Maine.Charlie's email I.D. is keen1981...add 1981 up and you get 19

The term "Oy", like the name of the billy bumbler from TDT is seen at the very end of the letter.

the monster cthun coming out of the ring of stones and the mention of other worlds