G.Bauchhenss, Militärische Grabdenkmäler. Germania Inferior. Bonn und Umgebung.CSIR Deutschland III.1 (Bonn 1978), 1.
A.S.Anderson, Roman Military Tombstones (Aylesbury 1984), p.44
V.A.Maxfield, The Military Decorations of the Roman Army (London 1981), plate 2a and text.
(The first two lines record the names of Marcus Caelius' freedmen, Marcus Caelius Privatus and Marcus Caelius Thiaminus) To Marcus Caelius, son of Titus, of the voting tribe Lemonia, from Bononia, first centurion of the eighteenth legion. At the age of 53 he fell in the Varian War, the bones (of his freedmen) may be interred here. His brother Caelius, son of Titus, of the tribe Lemonia, erected (this tombstone)