http://www.skyscrapercenter.com/building/hudson-terminal-building-south/11981 ,
https://skyscraperpage.com/cities/?buildingID=9075
https://skyscraperpage.com/cities/?buildingID=9074
https://en.todocoleccion.net/postcards-america/postal-new-york-singer-city-investing-and-hudson-terminal-buildings-detroit-publishing~x115079735
https://en.todocoleccion.net/postcards-america/new-york-city-hudson-terminal-and-tubes~x31079141
https://skyscraperpage.com/diagrams/?searchID=84594650&offset=50