Bott, S., ATWOOD, J., COLEMAN, A., ZHANG, H., & BOTT, S. (1989). Organic clays. Synthesis and structure of Na5[calix[4] arene sulfonate] � 12 H2O, K5[calix[4]arene sulfonate]�8 H2O, Rb5[calix[4]arene sulfonate]�5 H2O, and Cs5[calix[4] arene sulfonate] �4 H2O. Journal of Inclusion Phenomena and Molecular Recognition in Chemistry, 7(2), pp. 203-211. doi:10.1007/BF01060722

Bott, Simon, JL ATWOOD, AW COLEMAN, H. ZHANG, and SG BOTT. "Organic Clays. Synthesis and Structure of Na5[calix[4] Arene Sulfonate] � 12 H2O, K5[calix[4]arene Sulfonate]�8 H2O, Rb5[calix[4]arene Sulfonate]�5 H2O, and Cs5[calix[4] Arene Sulfonate] �4 H2O." Journal of Inclusion Phenomena and Molecular Recognition in Chemistry 7, no. 2 (1989): 203-211.

Bott, Simon, et al. "Organic Clays. Synthesis and Structure of Na5[calix[4] Arene Sulfonate] � 12 H2O, K5[calix[4]arene Sulfonate]�8 H2O, Rb5[calix[4]arene Sulfonate]�5 H2O, and Cs5[calix[4] Arene Sulfonate] �4 H2O." Journal of Inclusion Phenomena and Molecular Recognition in Chemistry 7.2 (1989): 203-211.