Recording sheets containing purine, pyrimidine, benzimidazole, imidazolidine, urazole, pyrazole, triazole, benzotriazole, tetrazole, and pyrazine compounds

Granted: Aug 19, 1997 Filed: May 25, 1995

This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.