1. BREZIS, H., CORON, J-J.: Large solutions for harmonic maps in two dimensions. Comm. Math. Phys.92, 203?215 (1983)
2. FEDERER, H.: Geometric Measure Theory. Heidelberg and New York: Springer 1969
3. HARDT, R., KINDERLEHRER, D., LIN, F. H.: Existence and partial regularity of static liquid crystal configurations. To appear in Comm. Math. Phys.
4. HILDEBRANDT, S.: Nonlinear elliptic systems and harmonic mappings. Symposium on Differential Geometry and Differential Equations. Biejing University 1980. New York. Science Press, Gordon & Breach(1982) 481?616
5. SCHOEN, R.: Analytic aspects of the harmonic map problem. Preprint