... Iwaniec and A. Lutoborski, “Integral estimates for < /b> null Lagrangians,” Archive for < /b> Rational Mechanicsand Analysis, vol. 125, no. 1, pp. 2 5–7 9, 1993.10 Z. Cao, G. Bao, and R. Li, “The Caccioppoli ... Illinois Journal of < /b> Mathematics,vol. 43, no. 4, pp. 61 3–6 32, 1999.4 G. Bao, A rλ-weighted integral inequalities for < /b> A- harmonic tensors,” Journal of < /b> MathematicalAnalysis and Applications, vol. ... conjugate p-harmonic differential forms,” Journal of < /b> Mathematical Analysisand Applications, vol. 227, no. 1, pp. 25 1–2 70, 1998.2 J. Heinonen, T. Kilpel¨ainen, and O. Martio, Nonlinear Potential...