background paper for Ball

tex/bibliography.bib

@@ -30,3 +30,16 @@
   title = {Nematic liquid crystals on curved surfaces: a thin film limit},
   journal = {Proceedings of the Royal Society A: Mathematical,  Physical and Engineering Sciences}
 }
+@article{q4-q4-Ball2008,
+  doi = {10.1080/15421400802430067},
+  url = {https://www.researchgate.net/profile/Arghir-Zarnescu/publication/228918756_Orientable_and_Non-Orientable_Line_Field_Models_for_Uniaxial_Nematic_Liquid_Crystals/links/02bfe51074dd2a2ff2000000/Orientable-and-Non-Orientable-Line-Field-Models-for-Uniaxial-Nematic-Liquid-Crystals.pdf},
+  year = {2008},
+  month = nov,
+  publisher = {Informa {UK} Limited},
+  volume = {495},
+  number = {1},
+  pages = {221/[573]--233/[585]},
+  author = {John M. Ball and Arghir Zarnescu},
+  title = {Orientable and Non-Orientable Line Field Models for Uniaxial Nematic Liquid Crystals},
+  journal = {Molecular Crystals and Liquid Crystals}
+}