@book{es_ThomI,
Title            =  "Minkowski Geometry",
Author           =  "Thompson, Anthony C.",
Publisher        =  "Cambridge University Press",
Year             =  "1996",
}

 
@article{es_Brisbin,
Title            =  "Taxicab Trigonometry",
Author           =  "Ruth Brisbin and Paul Artola",
Journal          =  "Pi My Epsilon Journal",
Volume           =  "8",
Pages            =  "89--95,",
Year             =  "1985",
}

 
@misc{es_TG3,
Title            =  "TaxicabGeometry and City Planning.",
howpublished     =  "http://www2.gvsu.edu/petersm/taxi.html.",
key              =  "URL_es_TG3"
}
 
@book{es_Hilbert,
Title            =  "Gedenkband",
Author           =  "David Hilbert",
Address          =  "Berlin, Heidelberg, New York",
Publisher        =  "Springer",
Year             =  "1971",
}
 
@book{es_GardnerGeometrie,
Title            =  "Geometrie mit Taxis, die K¨opfe der Hydra und andere mathematische Spielerein",
Author           =  "Martin Gardner",
Publisher        =  "Birkh{\"a}user",
Year             =  "1997",
}