Huisman, A. (2012). Spherical Bird Observatory: A former bunker of the Dutch Waterline was turned into a bird observatory. Topos.
Lua i Stíl Chicago (17ú heag.)Huisman, Arie. "Spherical Bird Observatory: A Former Bunker of the Dutch Waterline Was Turned into a Bird Observatory." Topos 2012.
Lua MLA (8ú heag.)Huisman, Arie. "Spherical Bird Observatory: A Former Bunker of the Dutch Waterline Was Turned into a Bird Observatory." Topos, 2012.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.