6-Substituted 2, 4-Diamino-5-methylpyrido [2, 3-d] pyrimidines as Inhibitors of Dihydrofolate Reductases from Pneumocystis carinii and Toxoplasma gondii and as Antitumor Agents - Gangjee, A; Vasudevan, A; Queener, S F (J med chem, 1995)
et al.