Of astronomical problems pertaining to dating Ptolemy's Almagest (the catalog of stars and other books), supposedly from the 2nd century AD.
Scientific papers
Fomenko - The Jump of the 2nd Derivative of the Moon's Elongation (1980).pdf
Fomenko, Kalashnikov, Nosovsky - Ptolemy's Almagest (1989).pdf
Fomenko, Kalashnikov, Nosovsky - The Geometry of Moving Stellar Configurations (1991).pdf
Fomenko, Kalashnikov, Nosovsky - The Dating of Ptolemy's Almagest (1992).pdf
Book
Fomenko, Kalashnikov, Nosovsky - Dating Ptolemy's Almagest [1993].pdf