B. B.  Das, Ajithkumar, T. G., Sinha, N., Opella, S. J., and Ramanathan, K. V., ?Cross- and axial-peak intensities in 2D-SLF experiments based on cross-polarization - the role of the initial density matrix?, Journal of Magnetic Resonance, vol. 185, no. 2, pp. 308-317, 2007.