1. ^{{cite journal | vauthors = Hitchings GH, Falco EA | title = The Identification of Guanine in Extracts of Girella Nigricans: The Specificity of Guanase | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 30 | issue = 10 | pages = 294–7 | date = Oct 1944 | pmid = 16578130 | pmc = 1078714 | doi = 10.1073/pnas.30.10.294 }}
2. ^{{cite journal | vauthors = Kalckar HM | title = Differential spectrophotometry of purine compounds by means of specific enzymes; studies of the enzymes of purine metabolism | journal = J. Biol. Chem. | volume = 167 | issue = 2 | pages = 461–75 | year = 1947 | pmid = 20285041 | doi = | url = }}
3. ^{{cite journal | vauthors = Rabinowitz JC, Barker HA | title = Purine fermentation by Clostridium cylindrosporum. II. Purine transformations | journal = The Journal of Biological Chemistry | volume = 218 | issue = 1 | pages = 161–73 | date = Jan 1956 | pmid = 13278325 }}
4. ^{{cite journal | vauthors = Firestein BL, Firestein BL, Brenman JE, Aoki C, Sanchez-Perez AM, El-Husseini AE, Bredt DS | title = Cypin: a cytosolic regulator of PSD-95 postsynaptic targeting | journal = Neuron | volume = 24 | issue = 3 | pages = 659–72 | year = 1999 | pmid = 10595517 | doi = 10.1016/S0896-6273(00)81120-4| url = }}