Charles Dickens' Biography
https://www.oxforddnb.com/view/10.1093/ref:odnb/9780198614128.001.0001/odnb-9780198614128-e-7599
The Oxford Dictionary of National Biography's in-depth biography of Dickens.
"The Signalman"
https://www.gutenberg.org/files/1289/1289-h/1289-h.htm#page312
Project Gutenberg eBook Three Ghost Stories by Charles Dickens, including the full text of "The Signalman."
BBC Ghost Stories for Christmas: "The Signalman"
https://www.youtube.com/watch?v=XL_4VHxdXng
BBC's 1976 adaptation of "The Signalman." Directed by Lawrence Gordon Clark and starring Denholm Elliott and Bernard Lloyd.
