1. A. O. Gel'fond, Transcendental and Algebraic Numbers, Dover, New York (1960).
2. M. Waldschmidt, ?Independance algebrique des valeurs de la fonction exponentielle,? Bull. Soc. Math. France,99, No. 4, 285?304 (1971).
3. A. A. Shmelev, ?On the problem of algebraic independence of algebraic powers of algebraic numbers,? Matem. Zametki,11, No. 6, 635?644 (1972).
4. A. O. Gel'fond, ?On algebraic independence of transcendental numbers of certain classes,? Usp. Matem. Nauk,4, No. 5, 14?48 (1949).
5. A. O. Gel'fond and N. I. Fel'dman, ?On a measure of the relative transcendence of certain numbers,? Izv. Akad. Nauk SSSR, Ser. Matem.,14, 493?500 (1950).