[1] V. PTÁK: 
Deux théorèmes de factorisation. Compter Rendus Ac. Sci. Paris 278 (1974), 1091-1094. 
MR 0341096[2] V. PTÁK: 
A theorem of the closed graph type. Manuscripts Math. 13 (1974), 109-130. 
MR 0348430[3] V. PTÁK: 
A quantitative refinement of the closed graph theorem. Czech. Math. Journal 99 (1974), 503-506. 
MR 0348431[4] V. PTÁK: Nondiscrete mathematical induction and iterative existence proofs. Linear Algebra and its Applications (in print).
[5] V. PTÁK: The rate of convergence of Newton's method. Numerische Mathematik (in print).
[6] V. PTÁK: A rate of convergence. Abh. aus dem Math. Seminar Hamburg (in  print).