I didn't read the thesis itself yet but I feel like some key point must be missing from the article. The "loop programs" described are nearly identical to the "abacus machine" presented in the textbook Computability and Logic (pp. 55-56 3rd ed.) which cites Joachim Lambek who published "How to Program an Infinite Abacus" in 1961 which seems to also be trivially close in structure (not merely equivalent).

Lambek in turn cites Melzak's "An Informal Arithmetical Approach to Computability and Computation" which not identical - it has transfer and arbitrary compare branch instructions - but that seems a compromise for pedagogical purposes as deriving both from the "abacus" seems fairly trivial to me.