1. General References;Chemistry of Heterocyclic Compounds: A Series Of Monographs;2008-01-02
2. Purine Syntheses from Imidazoles and Other Precursors;Chemistry of Heterocyclic Compounds: A Series Of Monographs;2008-01-02
3. Synthesis of N-substituted xanthines (review);Chemistry of Heterocyclic Compounds;1991-01
4. Volume 5 References;Comprehensive Heterocyclic Chemistry;1984
5. Purines;Comprehensive Heterocyclic Chemistry;1984