Celebratio Mathematica

M. G. Cran­dall and T. M. Lig­gett: “Gen­er­a­tion of semi-groups of non­lin­ear trans­form­a­tions on gen­er­al Banach spaces,” Am. J. Math. 93 : 2 (April 1971), pp. 265–​298. MR 287357 Zbl 0226.​47038 article

M. G. Cran­dall and T. M. Lig­gett: “A the­or­em and a counter­example in the the­ory of semig­roups of non­lin­ear trans­form­a­tions,” Trans. Am. Math. Soc. 160 (October 1971), pp. 263–​278. MR 301592 Zbl 0226.​47037 article