Site code XTB from Riese (2004); cited by Corpus of Maya Hieroglyphic Inscriptions (2012; 2016). Alternative name ‘Xtabla’ according to Teobert Maler (Mayer 2013: 84).
Location recorded the Castillo by Karl Herbert Mayer and Stephan Merk with a handheld Global Positioning System (GPS) in 1999.

Corpus of Maya Hieroglyphic Inscriptions (CMHI)
2012 Site Codes (updated July 2012). http://peabody.harvard.edu/files/cmhi/CMHI_SiteCodes_FINAL_2012_forWeb.pdf (by Barbara Fash). (accessed July 23, 2015)
2016 Site Codes (updated Februar 2016). https://www.peabody.harvard.edu/files/cmhi/CMHI_SiteCodes_FINAL_2016.pdf (by Barbara Fash). (accessed December 23, 2016)
Mayer, Karl Herbert
2013 The Maya Site of Xtablakal, Yucatán, Mexico. Mexicon 35(4): 84–86.
Riese, Berthold
2004 Abkürzungen für Maya-Ruinenorte mit Inschriften. Wayeb Notes 8. http://www.wayeb.org/notes/wayeb_notes0008.pdf (accessed July 23, 2015)