Haviland et al. n.d.

@misc{Haviland-et-al-nd,
  author       = {John Haviland, Stuart Robinson and Gutierrez, Esteban},
  howpublished = {online},
  title        = {An On-line Tzotzil Grammar},
  url          = {https://theswissbay.ch/pdf/Books/Linguistics/Mega%20linguistics%20pack/Central%20and%20Meso-America/Mayan/Tzotzil%20Grammar%20%28Haviland%2C%20Robinson%20%26%20Gutierrez%29.pdf},
  iso_code     = {tzz},
  olac_field   = {phonetics; typology; general_linguistics; phonology},
  wals_code    = {tzz}
}