| Zalman Usiskin and Jennifer Griffin, "The Classification of Quadrilaterals | |
|---|---|
| Owen Byer, Felix Lazebnik and Deirdre Smeltzer, Methods for Euclidean Geometry, Mathematical Association of America, 2010, pp | io, Retrieved 24-3-2020 page 8 |
A Study of Definition", Information Age Publishing, 2008, p.
10| io, Retrieved 24-3-2020 page 6 | |
|---|---|
.
22.
25