Site code YLS given by Corpus of Maya Hieroglyphic Inscriptions (1999:187-189; 2012; 2016); cited by Riese (2004), Mathews (2005).
Coordinates unverified.

Corpus of Maya Hieroglyphic Inscriptions (CMHI)
1999 Corpus of Maya Hieroglyphic Inscriptions. Volume 6, Part 3: Tonina (by Ian Graham and Peter Mathews). Cambridge, Massachusetts: Peabody Museum of Archaeology and Ethnology, Harvard University.
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)
Mathews, Peter
2005 Site Names and Codes. Foundation for the Advancement of Mesoamerican Studies (FAMSI) http://research.famsi.org/whos_who/sitenames_codes.htm (accessed July 23, 2015)
Riese, Berthold
2004 Abkürzungen für Maya-Ruinenorte mit Inschriften. Wayeb Notes 8. http://www.wayeb.org/notes/wayeb_notes0008.pdf (accessed July 23, 2015)
Stone, Andrea J.
1995 Images from the Underworld: Naj Tunich and the Tradition of Maya Cave Painting. University of Texas Press, Austin, TX.