CIMRM 437-455 - Miscellaneous finds. Circus Maximus Mithraeum, Rome
Here is a list of the other monuments, finds and inscriptions from the Circus Maximus mithraeum.
The Imago Romae site has the following interesting comment on the graffiti (CIMRM 454):
On the plaster of the wall to the left of the arch is preserved some graffiti, arranged in five rows. The reading and interpretation of this is still quite controversial. For some scholars, the reading would be: Magicas / inbiti fas / ey bene Gentio / Aternius / Biro, ... For others, limited to the first three lines, the reading would be instead: Magicas / inbictas / cede Degentio, ..., the latter identifying the author of the graffiti. All agree to the interpretation of the word "magicas", which should not be related to magic but to religious acts or sacred instruments.
C. Pietrangeli, "Il Mitreo del Palazzo dei Museo di Roma", Bullettino della Commissione archeologica Communale di Roma (cf. BCM). From 1939: Bullettino della Commissione archeologica del Governatorato di Roma. 68 (1940-41), 143ff; also separately in Monumenti di Roma 4, Roma 1941.
Antonio Insalaco, "DEO SOLI INVICTO MITHRAE: i misteri iniziatici nella Roma imperiale ed il Mitreo del Circo Massimo", Imago Romae, 5 Nov. 2008. Photography by Alfredo Corrao. Retrieved 28 Feb. 2014. An extremely useful and detailed site (in Italian). Unfortunately the site is already decaying and large images from the "gallery" are not found.