library

correspondence (reciprocal exchange of civilities, especially by letters)

to correspond (exchange messages, especially by postal letter, over a period of time); to communicate with letters

(mathematics) factorization

(mathematics) factor

written material, writing

epigraph

mosquito net

Kyūjitai form of 文献 (“literature; research materials; documents”)

paperweight / (computing slang, figuratively) brick (an electronic device, especially a heavy box-shaped one, that has become non-functional or obsolete)