For example he published Remarks on the elementary theory of differential equations as area of research in 1965 and A generalization of Laplace's transformation in 1966.
Halimbawa siya nai-publish Remarks sa elementarya teorya ng kaugalian equation bilang lugar ng pananaliksik sa 1,965 at isang kalahatan ng Laplace ang pagbabagong-anyo sa 1966.