Philadelphia City Hall

1. Great Tower of the City Hall, Philadelphia—Total Height, 547 Feet. Dans: Scientific American, v. 64, n. 23 (6 juin 1891), pp. 357.

   https://doi.org/10.1038/scientificamerican06061891-357

2. Jones, Jenny (2011): The Greatest Single Effort: Philadelphia's City Hall. Dans: Civil Engineering Magazine, v. 81, n. 7 (juillet 2011), pp. 44-46.

   https://doi.org/10.1061/ciegag.0000552

3. The Tower of the New City Hall, Philadelphia, Pa—The Loftiest Statue in the World. Dans: Scientific American, v. 71, n. 24 (15 décembre 1894), pp. 376.

   https://doi.org/10.1038/scientificamerican12151894-376