[ČV] K. ČUBA P. VOPĚNKA:
Real and imaginary classes in the alternative set theory. Comment. Math. Univ. Carolinae 20 (1979), 639-653.
MR 0555180
[K] H. J. KEISLER: Elementary Calculus: An Approach Using Infinitesimals. Prindle, Weber Schmidt, Boston, Massachusetts.
[KP] L. KIRBY J. PARIS:
Initital segments of models of Peano's axioms. Set Theory and Hierarchy Theory V, Bierutowice, Poland 1976, Lect. Notes in Math. 619, 211-226.
MR 0491157
[V] P. VOPĚNKA:
Mathematics in the alternative set theory. Teubner-Texte, Leipzig, 1979.
MR 0581368