The History of the Ballet Flat. StartUp FASHION. 2015-11-21 [2019-07-29]. (原始内容存档于2023-06-04) (美国英语). Stimpert, Desiree. Shoe Glossary: Ballerina Flats
Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; et al. Fermi Observations of the Very Hard Gamma-Ray Blazar PG 1553+113