W. A. Freeman, W. L. Mock en N.-Y. Shih, Cucurbituril. J. Am. Chem. Soc. 1981, 103, 7367-7368. DOI:10.1021/ja00414a070
W.A. Freeman, "Structures of the p-xylylenediammonium chloride and calcium hydrogensulfate adducts of the cavitand 'cucurbituril', C36H36N24O12". Acta Cryst. (1984) B40, 382-387. DOI:doi:10.1107/S0108768184002354