@article {MATHEDUC.05882841,
author = {Josefsson, Martin},
title = {More characterizations of tangential quadrilaterals.},
year = {2011},
journal = {Forum Geometricorum},
volume = {11},
issn = {1534-1178},
pages = {65-82},
publisher = {Florida Atlantic University, Department of Mathematical Sciences, Boca Raton, FL},
abstract = {A quadrilateral is said to be $tangential$ if there exists a circle tangent to its four sides. In this survey paper many proofs of not widely known characterizations of tangential quadrilaterals are given. Some characterizations involve only the lengths of the sides of the quadrilateral, while the most sophisticated ones involve even the radii of excircles defined by the sides and diagonals of the quadrilateral. The paper is well-written and is very interesting. It will make a good read even for undergraduates interested in elementary euclidean geometry.},
reviewer = {Antonio M. Oller (Zaragoza)},
msc2010 = {G40xx},
identifier = {2011f.00489},
}