• [1] H. A. Dye and R. S. Phillips, Groups of positive operators, Canad. J. Math. 8 (1956), 462–486. MR 0087906 (19,434a)
• [2] William Feller, On the generation of unbounded semi-groups of bounded linear operators, Ann. of Math. (2) 58 (1953), 166–174. MR 0055572 (14,1093g)
• [3] Einar Hille and Ralph S. Phillips, Functional analysis and semi-groups, American Mathematical Society Colloquium Publications, vol. 31, American Mathematical Society, Providence, R. I., 1957. rev. ed. MR 0089373 (19,664d)
• [4] H. F. Trotter, Approximation of semi-groups of operators, Pacific J. Math. 8 (1958), 887–919. MR 0103420 (21 #2190)

Bibliography

[1]

H. A. Dye and R. S. Phillips, Groups of positive operators, Canad. J. Math. vol. 8 (1956) pp. 462-486. MR 0087906 (19:434a)

[2]

W. Feller, On the generation of unbounded semi-groups of bounded linear operators, Ann. of Math. (2) vol. 58 (1953) pp. 166-174. MR 0055572 (14:1093g)

[3]

E. Hille and R. S. Phillips, Functional analysis and semi-groups, Amer. Math. Soc. Colloquium Publications, vol. 31, 1957. MR 0089373 (19:664d)

[4]

H. F. Trotter, Approximation of semi-groups of operators, Pacific J. Math. vol. 8 (1958) pp. 887-919. MR 0103420 (21:2190)