Over the years, a number of books have been published to aid the crossword solver faced with a word having one or two letters filled in. Such books can become prohibitively large, depending on the number of letters in the partially-solved word.
Eckler, A. Ross
Word Ways: Vol. 44
, Article 30.
Available at: https://digitalcommons.butler.edu/wordways/vol44/iss2/30