1. E. Makai, The first main theorem of P. Turán,Acta Math. Acad. Sci. Hung.,10 (1959), pp. 405–411.
2. R. Tijdeman, On van der Poorten's proofs of the main theorems of Turán,On the distribution of values of certain functions, Ch. I, Ph. D. Thesis (Amsterdam, 1969).
3. R. Tijdeman, On a generalisation of Turán's main theorems, Ch. II Ph. D. Thesis op. cit. (Amsterdam, 1969).
4. R. Tijdeman, Some theorems on general exponential polynomials, Ch. III Ph. D. Thesis op. cit. (Amsterdam, 1969).
5. P. Turán,Eine neue Methode in der Analysis und deren Anwendungen (Akadémiai Kiadó, Budapest, 1953).