Anonymous. 2007. Demographic Information On Sign Languages Around the World: Field Survey Notes. (SIL Electronic Survey Reports 2007-021 \url{http://www.sil.org/silesr/abstract.asp?ref=2007-021}).
@techreport{161311, author = {Anonymous}, institution = {SIL International, Dallas}, note = {SIL Electronic Survey Reports 2007-021 \url{http://www.sil.org/silesr/abstract.asp?ref=2007-021}}, title = {Demographic Information On Sign Languages Around the World: Field Survey Notes}, year = {2007}, hhtype = {overview}, inlg = {English [eng]}, src = {hh} }