** Odehnal, Boris
**
**Some triangle centers associated with the circles tangent to the excircles, 10 (2010) 35--40. **

**
**** Odom, Lucy H.
**
** (with W. G. Boskoff and B. D. Suceava) An elementary view on Gromov hyperbolic spaces, 12 (2012) 283--286. **

** Okumura, Hiroshi
**
** (with M. Watanabe) The Archimedean circles of Schoch and Woo, 4 (2004) 27--34. **

** (with M. Watanabe) The twin circles of Archimedes in a skewed arbelos, 4 (2004) 229--251. **

** (with M. Watanabe) The arbelos in $n$-aliquot parts, 5 (2005) 37--45. **

** (with M. Watanabe) A generalization of Power's Archimedean circles, 6 (2006) 103--105. **

** (with M. Watanabe) Characterizations of an infinite set of Archimedean circles, 7 (2007) 121--123. **

** (with M. Watanabe) Remarks on Woo's Archimedean circles, 7 (2007) 125--128. **

**More on twin circles of the skewed arbelos, 11 (2011) 139--144. **

**A note on Haga's theorems in paper folding, 14 (2014) 241--242.**

**Archimedean circles related to the Schoch line, 14 (2014) 369--370.**

**Two pairs of Archimedean circles derived from a square, 16 (2016) 23--24.**

**A remark on the arbelos and the regular star polygon, 18 (2018) 43--44.**

** (with S. Saitoh) Remarks for the twin circles of Archimedes in a skewed arbelos, 18 (2018) 99--102.**

**
**** Olah-Gal, Robert
**
** (with J. Sandor) On trigonometric proofs of the Steiner-Lehmus theorem, 9 (2009) 155--160. **

**
**** Oller-Marcen, Antonio M.
**
**The f-belos, 13 (2013) 103--111.**

**Archimedes' arbelos to the n-dimension, 16 (2016) 51--56. **

**
**** Olvera, Auturo
**
** (with C. E. Garza and M. C. Jorge) Areas and shapes of planar irregular polygons, 18 (2018) 17--36. **

**
**** Ong, Darren C.
**
**On a theorem of intersecting conics, 11 (2011) 95--107. **

**
**** Opincariu, Mihai
**
** (with D. Marinescu, M. Monea and M. Stroe) A sequence of triangles and geometric inequalities, 9 (2009) 291--295. **

**
**
** Osinkin, Sergey F. On the existence of a triangle with prescribed bisector lengths, 16 (2016) 399--405.
**

**
**** Oxman, Victor
**
**On the existence of triangles with given lengths of one side and two adjacent angle bisectors, 4 (2004) 215--218. **

**On the existence of triangles with given lengths of one side, the opposite and an adjacent angle bisectors, 5 (2005) 21--22. **

**On the existence of triangles with given circumcircle, incircle, and one additional element, 5 (2005) 165--171. **

**A purely geometric proof of the uniqueness of a triangle with prescribed angle bisectors, 8 (2008) 197--200. **

** (with M. Stupel) Why are the side lengths of the squares inscribed in a triangle so close to each other?, 13 (2013) 113--115.**

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