Alex Heller, (born on July 9, 1925, died January 31, 2008), was professor of mathematics at the Graduate School and University Center, CUNY in New York. He was a PhD student of Sammy Eilenberg and made some very important contributions to homotopy theory and to category theory.
Alex Heller, Homotopy resolutions of semi-simplicial complexes,Trans. Amer. Math. Soc. 80 (1955), 299-344, (available here.
Alex Heller, On the representability of homotopy functors J. London Math. Soc. (2) 23 (1981), no. 3, 551–562
Alex Heller, Homotopy theories , Memoirs of the American Mathematical Society, Vol. 71, No 383 (1988).
Alex Heller, Stable homotopy theories and stabilization , MR
Alex Heller, Robert A Di Paola, Dominical categories: recursion theory without elements, J. Symbolic Logic 52 (1987), no. 3, 594-635.
Alex Heller, Stable homotopy categories, Bull. Amer. Math. Soc. 74 (1968) 28-63
Alex Heller, On stochastic processes derived from Markov chains Ann. Math. Statist. 36 (1965) 1286-1291
Alex Heller, The loop-space functor in homological algebra, Trans. Amer. Math. Soc. 96 1960 382-394
Alex Heller, Homological algebra in abelian categories, Ann. of Math. (2) 68 1958 484-525
Alex Heller, Relative homotopy, J. London Math. Soc. (2) 44 (1991), no. 3, 537-552.