Bott, S., ATWOOD, J., ORR, G., HAMADA, F., VINCENT, R., BOTT, S., & ROBINSON, K. (1992). Calixarenes as second-sphere ligands for transition metal ions. Synthesis and crystal structure of [(H2O)5 Ni(NC5H5)]2(Na)[calix[4]arene sulfonate] � 3.5 H2O and [(H2O)4Cu(NC5H5)2]-(H3O)3 [calix[4]arene sulfonate] � 10 H2O. Journal of Inclusion Phenomena and Molecular Recognition in Chemistry, 14(1), pp. 37-46. doi:10.1007/BF01041364

Bott, Simon, JL ATWOOD, GW ORR, F. HAMADA, RL VINCENT, SG BOTT, and KD ROBINSON. "Calixarenes As Second-sphere Ligands for Transition Metal Ions. Synthesis and Crystal Structure of [(H2O)5 Ni(NC5H5)]2(Na)[calix[4]arene Sulfonate] � 3.5 H2O and [(H2O)4Cu(NC5H5)2]-(H3O)3 [calix[4]arene Sulfonate] � 10 H2O." Journal of Inclusion Phenomena and Molecular Recognition in Chemistry 14, no. 1 (1992): 37-46.

Bott, Simon, et al. "Calixarenes As Second-sphere Ligands for Transition Metal Ions. Synthesis and Crystal Structure of [(H2O)5 Ni(NC5H5)]2(Na)[calix[4]arene Sulfonate] � 3.5 H2O and [(H2O)4Cu(NC5H5)2]-(H3O)3 [calix[4]arene Sulfonate] � 10 H2O." Journal of Inclusion Phenomena and Molecular Recognition in Chemistry 14.1 (1992): 37-46.