S. Hawking, 1974, Nature, 248, 30, 10.1038/248030a0
S. Hawking, 1975, Commun. Math. Phys., 43, 199, 10.1007/BF02345020
B. K. Berger, 1972, Phys. Rev. D, 5, 2467, 10.1103/PhysRevD.5.2467
W. G. Unruh, 1974, Phys. Rev. D, 10, 3194, 10.1103/PhysRevD.10.3194
B. DeWitt, 1975, Phys. Rep., 19, 295, 10.1016/0370-1573(75)90051-4
S. Fulling, 1974, Ann. Phys. (N.Y.), 87, 76, 10.1016/0003-4916(74)90451-5
J. S. Schwinger, 1951, Phys. Rev., 82, 664, 10.1103/PhysRev.82.664
S. Fulling, 1974, Phys. Rev. D, 9, 341
R. Penrose, 1968, Battelle Rencontres
S. Fulling, 1973, Phys. Rev. D, 7, 2800, 10.1103/PhysRevD.7.2850
W. Rindler, 1966, Am. J. Phys., 34, 1174, 10.1119/1.1972547
P. C. W. Davies, 1975, J. Phys. A, 8, 609, 10.1088/0305-4470/8/4/022
G. Gibbons, 1975, Commun. Math. Phys., 44, 245, 10.1007/BF01609829
R. Wald, 1975, Commun. Math. Phys., 45, 9, 10.1007/BF01609863
D. Boulware, 1975, Phys. Rev. D, 11, 1404, 10.1103/PhysRevD.11.1404
A. Messiah, 1961, Quantum Mechanics
J. Bjorken, 1965, Relativistic Quantum Fields
R. Arnowitt, 1962, Gravitation, An Introduction to Current Research
K. Kuchař, 1971, Phys. Rev. D, 4, 955, 10.1103/PhysRevD.4.955
T. Regge, 1974, Ann. Phys. (N.Y.), 88, 286, 10.1016/0003-4916(74)90404-7
P. Cordero, 1975, Bull. Am. Phys. Soc., 20, 543
P. C. W. Davies, 1976, Phys. Rev. D, 13, 2720, 10.1103/PhysRevD.13.2720
