„Houses With No Furnace but Plenty of Heat“. New York Times. 2008 m. gruodžio 26 d. Nuoroda tikrinta 2008-12-27. „There are now an estimated 15,000 passive houses around the world, the vast majority built in the past few years in German-speaking countries or Scandinavia.“ {{cite news}}: Cite has empty unknown parameter: |coauthors= (pagalba)
