...It is well known that the celebrated Hille-Yosida theorem,
discovered independently by Hille  and Yosida , gave the first
characterization of the infinitesimal generator of a strongly
continuous semigroup of contractions. This was the beginning of a
systematic development of the theory of semigroups of bounded linear
operators. The bounded linear operator $A_λ$ appearing in the
sufficiency part of Yosida’s proof of this theorem is called the
Yosida approximation of $A$... ( preface i)
 Functional Analysis and Semi-groups, 3rd Print, Amer. Math. Soc. Colloq. Publ. Vol. 31, NY, 1948.
 On the differentiability and representation of one parameter semi-groups of linear operators, J. Math. Soc. Japan, 1, 15–21, 1948.
 Govindan, T. E. "Yosida Approximations of Stochastic Differential Equations in Infinite Dimensions and Applications." Probability theory and stochastic modelling ( 79 (2016).