References

1. Paul R. Halmos, intuïtieve verzamelingenleer, translated into Dutch from
   Naive Set Theory (PDF), D. van Nostrand Company, Inc., Princeton 1964
2. Alexander Abian and Samuel LaMacchia,
   ON THE CONSISTENCY AND INDEPENDENCE OF SOME SET-THEORETICAL AXIOMS
3. Wilhelm Ackermann, Mathematische Annalen / Zeitschriftenband (1937) / Artikel / 305 - 315,
   Die Widerspruchsfreiheit der allgemeinen Mengenlehre
4. The purpose of the $\sf ZFC$ Axiom of Infinity
5. Richard Kaye and Tin Lok Wong,
   On Interpretations of Arithmetic and Set Theory
6. Delphi Pascal software
7. Is it still possible for mathematicians to contribute to the theory of music?
8. What is the *middle* digit of $3^{100000}$?