• [1] J. W. Calkin, Abstract symmetric boundary conditions, Trans. Amer. Math. Soc. 45 (1939), no. 3, 369–442. MR 1501997, http://dx.doi.org/10.1090/S0002-9947-1939-1501997-7
• [2] J. L. B. Cooper, One-parameter semigroups of isometric operators in Hilbert space, Ann. of Math. (2) 48 (1947), 827–842. MR 0027129 (10,257a)
• [3] J. L. B. Cooper, Symmetric operators in Hilbert space, Proc. London Math. Soc. (2) 50 (1948), 11–55. MR 0024058 (9,446b)
• [4] Herbert Federer, Measure and area, Bull. Amer. Math. Soc. 58 (1952), 306–378. MR 0049289 (14,149e), http://dx.doi.org/10.1090/S0002-9904-1952-09586-0
• [5] William Feller, The parabolic differential equations and the associated semi-groups of transformations, Ann. of Math. (2) 55 (1952), 468–519. MR 0047886 (13,948a)
• [6] K. O. Friedrichs, Symmetric hyperbolic linear differential equations, Comm. Pure Appl. Math. 7 (1954), 345–392. MR 0062932 (16,44c)
• [7] 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)
• [8] Lars Hörmander, On the theory of general partial differential operators, Acta Math. 94 (1955), 161–248. MR 0076151 (17,853d)
• [9] M. S. Livšic, On spectral decomposition of linear nonself-adjoint operators, Mat. Sbornik N.S. 34(76) (1954), 145–199 (Russian). MR 0062955 (16,48f)
• [10] B. R. Mukminov, On expansion with respect to the eigenfunctions of dissipative kernels, Dokl. Akad. Nauk SSSR (N.S.) 99 (1954), 499–502 (Russian). MR 0068106 (16,830d)
• [11] B. de Sz. Nagy, Spektraldarstellung linearer Transformationen des Hilbertschen Raumes, Ergebnisse d. Math. vol. 5 (1942).
• [12] R. S. Phillips, Dissipative hyperbolic systems, Trans. Amer. Math. Soc. 86 (1957), 109–173. MR 0090748 (19,863d), http://dx.doi.org/10.1090/S0002-9947-1957-0090748-2
• [13] M. I. Višik, On general boundary problems for elliptic differential equations, Trudy Moskov. Mat. Obšč. 1 (1952), 187–246 (Russian). MR 0051404 (14,473d)
• [14] Kôsaku Yosida, An operator-theoretical integration of the wave equation, J. Math. Soc. Japan 8 (1956), 79–92. MR 0107085 (21 #5812)

Bibliography

[1]

J. W. Calkin, Abstract symmetric boundary conditions, Trans. Amer. Math. Soc. vol. 45 (1939) pp. 369-442. MR 1501997

[2]

J. L. B. Cooper, One parameter semi-groups of isometric operators in Hilbert space, Ann. of Math. vol. 48 (2) (1947) pp. 827-842. MR 0027129 (10:257a)

[3]

-, Symmetric operators in Hilbert space, Proc. London Math. Soc. vol. 50 (2) (1948) pp. 11-15. MR 0024058 (9:446b)

[4]

H. Federer, Measure and area, Bull. Amer. Math. Soc. vol. 58 (1952) pp. 306-378. MR 0049289 (14:149e)

[5]

W. Feller, The parabolic differential equations and the associated semi-groups of transformations, Ann. of Math. vol. 55 (1952) pp. 468-519. MR 0047886 (13:948a)

[6]

K. O. Friedrichs, Symmetric hyperbolic linear differential equations, Comm. Pure Appl. Math. vol. 7 (1954) pp. 345-392. MR 0062932 (16:44c)

[7]

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

[8]

Lars Hörmander, General partial differential operators, Acta Math. vol. 94 (1955) pp. 161-248. MR 0076151 (17:853d)

[9]

M. S. Livšlc, On the spectral decomposition of linear nonself-adjoint operators, Mat. Sbornik, N. S. vol. 34 (76) (1954) pp. 145-199. MR 0062955 (16:48f)

[10]

B. R. Mukminov, On expansions with respect to the eigenfunctions of dissipative kernels, Doklady Akad. Nauk. SSSR, N. S. vol. 99 (1954) pp. 499-502. MR 0068106 (16:830d)

[11]

B. de Sz. Nagy, Spektraldarstellung linearer Transformationen des Hilbertschen Raumes, Ergebnisse d. Math. vol. 5 (1942).

[12]

R. S. Phillips, Dissipative hyperbolic systems, Trans. Amer. Math. Soc. vol. 86 (1957) pp. 109-173. MR 0090748 (19:863d)

[13]

M. I. Višik, On general boundary problems for elliptic differential equations, Trudy Moskov. Mat. Obšč. vol. 1 (1952) pp. 187-246. MR 0051404 (14:473d)

[14]

Kôsaku Yosida, An operator-theoretical integration of the wave equation, J. Math. Soc. Japan vol. 8 (1956) pp. 79-92. MR 0107085 (21:5812)