Philadelphia City Hall

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

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

2. Jones, Jenny (2011): The Greatest Single Effort: Philadelphia's City Hall. In: Civil Engineering Magazine, v. 81, n. 7 (Juli 2011), S. 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. In: Scientific American, v. 71, n. 24 (15 Dezember 1894), S. 376.

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