@book{Bybee-et-al-1994,
  address    = {Chicago},
  author     = {Bybee, Joan L. and Perkins, Revere and Pagliuca, William},
  publisher  = {The University of Chicago Press},
  title      = {The evolution of grammar: Tense, aspect and modality in the languages of the world},
  year       = {1994},
  iso_code   = {chk; ktd; chy; cao; cdm; bzq; byx; lao; eus; shs; bfa; enn; bgp; zun; lhu; tuo; yss; kyh; cnh; udm; axb; ktz; scs; sba; xsl; ons; toj; knc; bpu; mev; tah; yue; ood; jiv; ygr; abk; raw; gvn; mph; rbb; cod; dru; kgo; cpa; mwe; gym; upv; kna; bxm; pce; tgg; nir; cab; meu; unp; nak; tem; awn; caq; mrt; nmu; uig; hla; aly; kdh; kxu; thv; pag; mai; mya; tpi; tig},
  olac_field = {syntax; general_linguistics; typology},
  wals_code  = {tne; kya; tah; pnn; cnt; krk; cpl; bar; juh; bui; tug; mai; wor; blc; lai; tpi; mne; tem; toj; bon; udm; mrg; hal; uyg; shu; cpn; nbr; plg; ood; yes; knr; bsq; abi; atc; cyn; brm; nak; ruk; cbo; zun; lah; kro; tgr; ngm; ygr; kui; sla; coc; mwe; knk; awn; gug; tga; tuc; aly; mau; jiv; abk; raw; mtu; egn; bng; but; nim; cuu; lao; ono; nca; grf; man}
}