A Convenient Synthesis of Fluorinated Pyrazolo[3,4-b]pyridine and Pyrazolo[3,4-d]pyrimidine Nucleosides - Iaroshenko, Viktor O.; Sevenard, Dmitri V.; Kotljarov, Anton; Volochnyuk, Dmitriy M.; Tolmachev, Andrei O.; Sosnovskikh, Vyacheslav Ya. (Synthesis, 2009)