adstex automatically identifies all citation keys in a TeX source file and builds the corresponding bibliography file (.bib file) by fetching the reference information from NASA's Astrophysics Data System (ADS). adstex recognizes all variants of the cite commands in TeX, and works with various styles of citation keys, including arXiv IDs, DOIs, and ADS bibcodes. When a citation key is in the format of first-author name and year, adstex will query NASA's ADS and return a list of possible reference matches for the user to select the intended one. When a reference entry has updated information on NASA's ADS, adstex can detect such changes and fetch the new information and update the user's bibliography file. adstex supports any reference entry that is available on NASA's ADS, and allows the authors to write papers without manually searching for the bibliography entries.