1. Bundschuh, P.: Irrationalitätsmaße füre a ,a?0 rational oder Liouville-Zahl. Math. Ann.192, 229?242 (1971)
2. Fel'dman, N.I., Shidlovsky, A.B.: The development and present state of the theory of transcendental numbers. Uspehi Mat. Nauk22, Nr. 3, 3?81 (1967) [russ.]; engl. Transl.: Russian Math. Surveys22, Nr. 3, 1?79 (1967)
3. Galochkin, A.I.: A lower bound for linear forms in values of certain hypergeometric functions. Mat. Zametki8, 19?28 (1970) [russ.]; engl. Transl.: Math. Notes8, 478?484 (1970)
4. Galochkin, A.I.: The sharpening of the bounds on certain linear forms. Mat. Zametki20, 35?45 (1976) [russ.]; engl. Transl.: Math. Notes20, 575?581 (1976)
5. Galochkin, A.I.: Arithmetic properties of the values of certain entire hypergeometric functions. Sibirsk. Mat. ?.17, 1220?1235 (1976) [russ.]; engl. Transl.; Siberian Math. J.17, 894?904 (1976)