T. S. Chu, “Geometrical representation of Gaussian beam propagation,” Bell Sys. Tech. J., vol. 45, pp. 287–299, February1966.

A. G. Fox, T. Li, “Effect of gain saturation on the oscillating modes of optical masers,” IEEE J. of Quantum Electronics, vol. QE-2, p. lxii, April1966.

H. Hochstadt, “On the eigenvalue of a class of integral equations arising in laser theory,” SIAM Rev., vol. 8, pp. 62–65, January1966.

[CrossRef]

J. A. Cochran, “The existence of eigenvalues for the integral equations of laser theory,” Bell Sys. Tech. J., vol. 44, pp. 77–88, January1965.

H. Kogelnik, “Imaging of optical mode—Resonators with internal lenses,” Bell Sys. Tech. J., vol. 44, pp. 455–494, March1965.

H. Statz, C. L. Tang, “Problem of mode deformation in optical masers,” J. Appl. Phys., vol. 36, pp. 1816–1819, June1965.

[CrossRef]

A. E. Siegman, “Unstable optical resonators for laser applications,” Proc. IEEE, vol. 53, pp. 277–287, March1965.

[CrossRef]

T. Li, “Diffraction loss and selection of modes in maser resonators with circular mirrors,” Bell Sys. Tech. J., vol. 44, pp. 917–932, May–June, 1965.

H. Kogelnik, “On the propagation of Gaussian beams of light through lenslike media including those with a loss or gain variation,” Appl. Opt., vol. 4, pp. 1562–1569, December1965.

[CrossRef]

W. Streifer, “Optical resonator modes—rectangular reflectors of spherical curvature,” J. Opt. Soc. Am., vol. 55, pp. 868–877, July1965

[CrossRef]

L. Bergstein, H. Schachter, “Resonant modes of optic cavities of small Fresnel numbers,” J. Opt. Soc. Am., vol. 55, pp. 1226–1233, October1965.

[CrossRef]

J. C. Heurtley, W. Streifer, “Optical resonator modes—circular reflectors of spherical curvature,” J. Opt. Soc. Am., vol. 55, pp. 1472–1479, November1965.

[CrossRef]

S. R. Barone, M. C. Newstein, “Fabry-Perot resonances at small Fresnel numbers,” Appl. Opt., vol. 3, p. 1194, October1964.

[CrossRef]

T. Li, “Dual forms of the Gaussian beam chart,” Appl. Opt., vol. 3, pp. 1315–1317, November1964.

[CrossRef]

D. Slepian, “Prolate spheroidal wave functions, Fourier analysis and uncertainty—IV: Extensions to many dimensions; generalized prolate spheroidal functions,” Bell Svs. Tech. J., vol. 43, pp. 3009–3057, November1964.

S. A. Collins, “Analysis of optical resonators involving focusing elements,” Appl. Opt., vol. 3, pp. 1263–1275, November1964.

[CrossRef]

M. Bertolotti, “Matrix representation of geometrical properties of laser cavities,” Nuovo Cimento, vol. 32, pp. 1242–1257, June1964.V. P. Bykov, L. A. Vainshtein, “Geometrical optics of open resonators,” JETP (USSR), vol. 47, pp. 508–517, August1964. B. Macke, “Laser cavities in geometrical optics approximation,” J. Pys. (Paris), vol. 26, pp. 104A–112A, March1965. W. K. Kahn, “Geometric optical derivation of formula for the variation of the spot size in a spherical mirror resonator,” Appl. Opt., vol. 4, pp. 758–759, June1965.

[CrossRef]

J. P. Gordon, H. Kogelnik, “Equivalence relations among spherical mirror optical resonators,” Bell Sys. Tech. J., vol. 43, pp. 2873–2886, November1964.

D. J. Newman, S. P. Morgan, “Existence of eigenvalues of a class of integral equations arising in laser theory,” Bell Sys. Tech. J., vol. 43, pp. 113–126, January1964.

D. Gloge, “Calculations of Fabry-Perot laser resonators by scattering matrices,” Arch. Elect. Ubertrag., vol. 18, pp. 197–203, March1964.

J. P. Gordon, “A circle diagram for optical resonators,” Bell Sys. Tech. J., vol. 43, pp. 1826–1827, July1964. M. J. Offerhaus, “Geometry of the radiation field for a laser interferometer,” Philips Res. Rept., vol. 19, pp. 520–523, December1964.

A. G. Fox, T. Li, “Modes in a maser interferometer with curved and tilted mirrors,” Proc. IEEE, vol. 51, pp. 80–89, January1963.

[CrossRef]

L. A. Vainshtein, “Open resonators for lasers,” JETP (USSR), vol. 44, pp. 1050–1067, March1963; Sov. Phys. JETP, vol. 17, pp. 709–719, September1963.

S. R. Barone, “Resonances of the Fabry-Perot laser,” J. Appl. Phys., vol. 34, pp. 831–843, April1963.

[CrossRef]

H. Kogelnik, W. W. Rigrod, “Visual display of isolated optical-resonator modes,” Proc. IRE (Correspondence), vol. 50, p. 220, February1962.

G. D. Boyd, H. Kogelnik, “Generalized confocal resonator theory,” Bell Sys. Tech. J., vol. 41, pp. 1347–1369, July1962.

G. Goubau, F. Schwering, “On the guided propagation of electromagnetic wave beams,” IRE Trans. on Antennas and Propagation, vol. AP-9, pp. 248–256, May1961.

[CrossRef]

J. R. Pierce, “Modes in sequences of lenses,” Proc. Nat’l Acad. Sci., vol. 47, pp. 1808–1813, November1961.

G. D. Boyd, J. P. Gordon, “Confocal multimode resonator for millimeter through optical wavelength masers,” Bell Sys. Tech. J., vol. 40, pp. 489–508, March1961.

F. Schwering, “Reiterative wave beams of rectangular symmetry,” Arch. Elect. Übertrag., vol. 15, pp. 555–564, December1961

D. Slepian, H. O. Pollak, “Prolate spheroidal wave functions, Fourier analysis and uncertainty—I,” Bell Sys. Tech. J., vol. 40, pp. 43–64, January1961.

A. G. Fox, T. Li, “Resonant modes in an optical maser,” Proc. IRE(Correspondence), vol. 48, pp. 1904–1905, November1960; “Resonant modes in a maser interferometer,” Bell Sys. Tech. J., vol. 40, pp. 453–488, March1961.

A. M. Prokhorov, “Molecular amplifier and generator for sub-millimeter waves,” JETP (USSR), vol. 34, pp. 1658–1659, June1958; Sov. Phys. JETP, vol. 7, pp. 1140–1141, December1958.

A. L. Schawlow, C. H. Townes, “Infrared and optical masers,” Phys. Rev., vol. 29, pp. 1940–1949, December1958.

[CrossRef]

S. R. Barone, M. C. Newstein, “Fabry-Perot resonances at small Fresnel numbers,” Appl. Opt., vol. 3, p. 1194, October1964.

[CrossRef]

S. R. Barone, “Resonances of the Fabry-Perot laser,” J. Appl. Phys., vol. 34, pp. 831–843, April1963.

[CrossRef]

M. Bertolotti, “Matrix representation of geometrical properties of laser cavities,” Nuovo Cimento, vol. 32, pp. 1242–1257, June1964.V. P. Bykov, L. A. Vainshtein, “Geometrical optics of open resonators,” JETP (USSR), vol. 47, pp. 508–517, August1964. B. Macke, “Laser cavities in geometrical optics approximation,” J. Pys. (Paris), vol. 26, pp. 104A–112A, March1965. W. K. Kahn, “Geometric optical derivation of formula for the variation of the spot size in a spherical mirror resonator,” Appl. Opt., vol. 4, pp. 758–759, June1965.

[CrossRef]

G. D. Boyd, H. Kogelnik, “Generalized confocal resonator theory,” Bell Sys. Tech. J., vol. 41, pp. 1347–1369, July1962.

G. D. Boyd, J. P. Gordon, “Confocal multimode resonator for millimeter through optical wavelength masers,” Bell Sys. Tech. J., vol. 40, pp. 489–508, March1961.

W. Brower, Matrix Methods in Optical Instrument Design. New York: Benjamin, 1964. E. L. O’Neill, Introduction to Statistical Optics. Reading, Mass.: Addison-Wesley, 1963.

T. S. Chu, “Geometrical representation of Gaussian beam propagation,” Bell Sys. Tech. J., vol. 45, pp. 287–299, February1966.

J. A. Cochran, “The existence of eigenvalues for the integral equations of laser theory,” Bell Sys. Tech. J., vol. 44, pp. 77–88, January1965.

G. A. Deschamps, P. E. Mast, “Beam tracing and applications,” in Proc. Symposium on Quasi-Optics. New York: Polytechnic Press, 1964, pp. 379–395.

R. H. Dicke, “Molecular amplification and generation systems and methods,” U. S. Patent2 851 652, September9, 1958.

A. G. Fox, T. Li, “Effect of gain saturation on the oscillating modes of optical masers,” IEEE J. of Quantum Electronics, vol. QE-2, p. lxii, April1966.

A. G. Fox, T. Li, “Modes in a maser interferometer with curved and tilted mirrors,” Proc. IEEE, vol. 51, pp. 80–89, January1963.

[CrossRef]

A. G. Fox, T. Li, “Resonant modes in an optical maser,” Proc. IRE(Correspondence), vol. 48, pp. 1904–1905, November1960; “Resonant modes in a maser interferometer,” Bell Sys. Tech. J., vol. 40, pp. 453–488, March1961.

A. G. Fox, T. Li, “Modes in a maser interferometer with curved mirrors,” in Proc. Third International Congress on Quantum Electronics. New York: Columbia University Press, 1964, pp. 1263–1270.

A. G. Fox, T. Li, to be published.

D. Gloge, “Calculations of Fabry-Perot laser resonators by scattering matrices,” Arch. Elect. Ubertrag., vol. 18, pp. 197–203, March1964.

J. P. Gordon, H. Kogelnik, “Equivalence relations among spherical mirror optical resonators,” Bell Sys. Tech. J., vol. 43, pp. 2873–2886, November1964.

J. P. Gordon, “A circle diagram for optical resonators,” Bell Sys. Tech. J., vol. 43, pp. 1826–1827, July1964. M. J. Offerhaus, “Geometry of the radiation field for a laser interferometer,” Philips Res. Rept., vol. 19, pp. 520–523, December1964.

G. D. Boyd, J. P. Gordon, “Confocal multimode resonator for millimeter through optical wavelength masers,” Bell Sys. Tech. J., vol. 40, pp. 489–508, March1961.

G. Goubau, F. Schwering, “On the guided propagation of electromagnetic wave beams,” IRE Trans. on Antennas and Propagation, vol. AP-9, pp. 248–256, May1961.

[CrossRef]

G. Goubau, “Optical relations for coherent wave beams,” in Electromagnetic Theory and Antennas. New York: Macmillan, 1963, pp. 907–918.

J. C. Heurtley, W. Streifer, “Optical resonator modes—circular reflectors of spherical curvature,” J. Opt. Soc. Am., vol. 55, pp. 1472–1479, November1965.

[CrossRef]

J. C. Heurtley, “Hyperspheroidal functions—optical resonators with circular mirrors,” in Proc. Symposium on Quasi-Optics. New York: Polytechnic Press, 1964, pp. 367–375.

F. B. Hildebrand, Methods of Applied Mathematics. Englewood Cliffs, N. J.: Prentice Hall, 1952, pp. 412–413.

H. Hochstadt, “On the eigenvalue of a class of integral equations arising in laser theory,” SIAM Rev., vol. 8, pp. 62–65, January1966.

[CrossRef]

H. Kogelnik, “On the propagation of Gaussian beams of light through lenslike media including those with a loss or gain variation,” Appl. Opt., vol. 4, pp. 1562–1569, December1965.

[CrossRef]

H. Kogelnik, “Imaging of optical mode—Resonators with internal lenses,” Bell Sys. Tech. J., vol. 44, pp. 455–494, March1965.

J. P. Gordon, H. Kogelnik, “Equivalence relations among spherical mirror optical resonators,” Bell Sys. Tech. J., vol. 43, pp. 2873–2886, November1964.

H. Kogelnik, W. W. Rigrod, “Visual display of isolated optical-resonator modes,” Proc. IRE (Correspondence), vol. 50, p. 220, February1962.

G. D. Boyd, H. Kogelnik, “Generalized confocal resonator theory,” Bell Sys. Tech. J., vol. 41, pp. 1347–1369, July1962.

H. Kogelnik, “Modes in optical resonators,” in Lasers, A. K. Levine, Ed. New York: Dekker, 1966.

A. G. Fox, T. Li, “Effect of gain saturation on the oscillating modes of optical masers,” IEEE J. of Quantum Electronics, vol. QE-2, p. lxii, April1966.

T. Li, “Diffraction loss and selection of modes in maser resonators with circular mirrors,” Bell Sys. Tech. J., vol. 44, pp. 917–932, May–June, 1965.

T. Li, “Dual forms of the Gaussian beam chart,” Appl. Opt., vol. 3, pp. 1315–1317, November1964.

[CrossRef]

A. G. Fox, T. Li, “Modes in a maser interferometer with curved and tilted mirrors,” Proc. IEEE, vol. 51, pp. 80–89, January1963.

[CrossRef]

A. G. Fox, T. Li, “Resonant modes in an optical maser,” Proc. IRE(Correspondence), vol. 48, pp. 1904–1905, November1960; “Resonant modes in a maser interferometer,” Bell Sys. Tech. J., vol. 40, pp. 453–488, March1961.

A. G. Fox, T. Li, “Modes in a maser interferometer with curved mirrors,” in Proc. Third International Congress on Quantum Electronics. New York: Columbia University Press, 1964, pp. 1263–1270.

A. G. Fox, T. Li, to be published.

G. A. Deschamps, P. E. Mast, “Beam tracing and applications,” in Proc. Symposium on Quasi-Optics. New York: Polytechnic Press, 1964, pp. 379–395.

D. J. Newman, S. P. Morgan, “Existence of eigenvalues of a class of integral equations arising in laser theory,” Bell Sys. Tech. J., vol. 43, pp. 113–126, January1964.

D. J. Newman, S. P. Morgan, “Existence of eigenvalues of a class of integral equations arising in laser theory,” Bell Sys. Tech. J., vol. 43, pp. 113–126, January1964.

J. R. Pierce, “Modes in sequences of lenses,” Proc. Nat’l Acad. Sci., vol. 47, pp. 1808–1813, November1961.

J. R. Pierce, Theory and Design of Electron Beams. New York: Van Nostrand, 1954, p. 194.

D. Slepian, H. O. Pollak, “Prolate spheroidal wave functions, Fourier analysis and uncertainty—I,” Bell Sys. Tech. J., vol. 40, pp. 43–64, January1961.

A. M. Prokhorov, “Molecular amplifier and generator for sub-millimeter waves,” JETP (USSR), vol. 34, pp. 1658–1659, June1958; Sov. Phys. JETP, vol. 7, pp. 1140–1141, December1958.

H. Kogelnik, W. W. Rigrod, “Visual display of isolated optical-resonator modes,” Proc. IRE (Correspondence), vol. 50, p. 220, February1962.

A. L. Schawlow, C. H. Townes, “Infrared and optical masers,” Phys. Rev., vol. 29, pp. 1940–1949, December1958.

[CrossRef]

G. Goubau, F. Schwering, “On the guided propagation of electromagnetic wave beams,” IRE Trans. on Antennas and Propagation, vol. AP-9, pp. 248–256, May1961.

[CrossRef]

F. Schwering, “Reiterative wave beams of rectangular symmetry,” Arch. Elect. Übertrag., vol. 15, pp. 555–564, December1961

A. E. Siegman, “Unstable optical resonators for laser applications,” Proc. IEEE, vol. 53, pp. 277–287, March1965.

[CrossRef]

D. Slepian, “Prolate spheroidal wave functions, Fourier analysis and uncertainty—IV: Extensions to many dimensions; generalized prolate spheroidal functions,” Bell Svs. Tech. J., vol. 43, pp. 3009–3057, November1964.

D. Slepian, H. O. Pollak, “Prolate spheroidal wave functions, Fourier analysis and uncertainty—I,” Bell Sys. Tech. J., vol. 40, pp. 43–64, January1961.

H. Statz, C. L. Tang, “Problem of mode deformation in optical masers,” J. Appl. Phys., vol. 36, pp. 1816–1819, June1965.

[CrossRef]

J. C. Heurtley, W. Streifer, “Optical resonator modes—circular reflectors of spherical curvature,” J. Opt. Soc. Am., vol. 55, pp. 1472–1479, November1965.

[CrossRef]

W. Streifer, “Optical resonator modes—rectangular reflectors of spherical curvature,” J. Opt. Soc. Am., vol. 55, pp. 868–877, July1965

[CrossRef]

H. Statz, C. L. Tang, “Problem of mode deformation in optical masers,” J. Appl. Phys., vol. 36, pp. 1816–1819, June1965.

[CrossRef]

A. L. Schawlow, C. H. Townes, “Infrared and optical masers,” Phys. Rev., vol. 29, pp. 1940–1949, December1958.

[CrossRef]

L. A. Vainshtein, “Open resonators for lasers,” JETP (USSR), vol. 44, pp. 1050–1067, March1963; Sov. Phys. JETP, vol. 17, pp. 709–719, September1963.

S. A. Collins, “Analysis of optical resonators involving focusing elements,” Appl. Opt., vol. 3, pp. 1263–1275, November1964.

[CrossRef]

H. Kogelnik, “On the propagation of Gaussian beams of light through lenslike media including those with a loss or gain variation,” Appl. Opt., vol. 4, pp. 1562–1569, December1965.

[CrossRef]

S. R. Barone, M. C. Newstein, “Fabry-Perot resonances at small Fresnel numbers,” Appl. Opt., vol. 3, p. 1194, October1964.

[CrossRef]

T. Li, “Dual forms of the Gaussian beam chart,” Appl. Opt., vol. 3, pp. 1315–1317, November1964.

[CrossRef]

D. Gloge, “Calculations of Fabry-Perot laser resonators by scattering matrices,” Arch. Elect. Ubertrag., vol. 18, pp. 197–203, March1964.

F. Schwering, “Reiterative wave beams of rectangular symmetry,” Arch. Elect. Übertrag., vol. 15, pp. 555–564, December1961

D. Slepian, “Prolate spheroidal wave functions, Fourier analysis and uncertainty—IV: Extensions to many dimensions; generalized prolate spheroidal functions,” Bell Svs. Tech. J., vol. 43, pp. 3009–3057, November1964.

D. Slepian, H. O. Pollak, “Prolate spheroidal wave functions, Fourier analysis and uncertainty—I,” Bell Sys. Tech. J., vol. 40, pp. 43–64, January1961.

J. P. Gordon, H. Kogelnik, “Equivalence relations among spherical mirror optical resonators,” Bell Sys. Tech. J., vol. 43, pp. 2873–2886, November1964.

D. J. Newman, S. P. Morgan, “Existence of eigenvalues of a class of integral equations arising in laser theory,” Bell Sys. Tech. J., vol. 43, pp. 113–126, January1964.

J. A. Cochran, “The existence of eigenvalues for the integral equations of laser theory,” Bell Sys. Tech. J., vol. 44, pp. 77–88, January1965.

G. D. Boyd, J. P. Gordon, “Confocal multimode resonator for millimeter through optical wavelength masers,” Bell Sys. Tech. J., vol. 40, pp. 489–508, March1961.

G. D. Boyd, H. Kogelnik, “Generalized confocal resonator theory,” Bell Sys. Tech. J., vol. 41, pp. 1347–1369, July1962.

H. Kogelnik, “Imaging of optical mode—Resonators with internal lenses,” Bell Sys. Tech. J., vol. 44, pp. 455–494, March1965.

T. S. Chu, “Geometrical representation of Gaussian beam propagation,” Bell Sys. Tech. J., vol. 45, pp. 287–299, February1966.

J. P. Gordon, “A circle diagram for optical resonators,” Bell Sys. Tech. J., vol. 43, pp. 1826–1827, July1964. M. J. Offerhaus, “Geometry of the radiation field for a laser interferometer,” Philips Res. Rept., vol. 19, pp. 520–523, December1964.

T. Li, “Diffraction loss and selection of modes in maser resonators with circular mirrors,” Bell Sys. Tech. J., vol. 44, pp. 917–932, May–June, 1965.

A. G. Fox, T. Li, “Effect of gain saturation on the oscillating modes of optical masers,” IEEE J. of Quantum Electronics, vol. QE-2, p. lxii, April1966.

G. Goubau, F. Schwering, “On the guided propagation of electromagnetic wave beams,” IRE Trans. on Antennas and Propagation, vol. AP-9, pp. 248–256, May1961.

[CrossRef]

H. Statz, C. L. Tang, “Problem of mode deformation in optical masers,” J. Appl. Phys., vol. 36, pp. 1816–1819, June1965.

[CrossRef]

S. R. Barone, “Resonances of the Fabry-Perot laser,” J. Appl. Phys., vol. 34, pp. 831–843, April1963.

[CrossRef]

W. Streifer, “Optical resonator modes—rectangular reflectors of spherical curvature,” J. Opt. Soc. Am., vol. 55, pp. 868–877, July1965

[CrossRef]

L. Bergstein, H. Schachter, “Resonant modes of optic cavities of small Fresnel numbers,” J. Opt. Soc. Am., vol. 55, pp. 1226–1233, October1965.

[CrossRef]

J. C. Heurtley, W. Streifer, “Optical resonator modes—circular reflectors of spherical curvature,” J. Opt. Soc. Am., vol. 55, pp. 1472–1479, November1965.

[CrossRef]

L. A. Vainshtein, “Open resonators for lasers,” JETP (USSR), vol. 44, pp. 1050–1067, March1963; Sov. Phys. JETP, vol. 17, pp. 709–719, September1963.

A. M. Prokhorov, “Molecular amplifier and generator for sub-millimeter waves,” JETP (USSR), vol. 34, pp. 1658–1659, June1958; Sov. Phys. JETP, vol. 7, pp. 1140–1141, December1958.

M. Bertolotti, “Matrix representation of geometrical properties of laser cavities,” Nuovo Cimento, vol. 32, pp. 1242–1257, June1964.V. P. Bykov, L. A. Vainshtein, “Geometrical optics of open resonators,” JETP (USSR), vol. 47, pp. 508–517, August1964. B. Macke, “Laser cavities in geometrical optics approximation,” J. Pys. (Paris), vol. 26, pp. 104A–112A, March1965. W. K. Kahn, “Geometric optical derivation of formula for the variation of the spot size in a spherical mirror resonator,” Appl. Opt., vol. 4, pp. 758–759, June1965.

[CrossRef]

A. L. Schawlow, C. H. Townes, “Infrared and optical masers,” Phys. Rev., vol. 29, pp. 1940–1949, December1958.

[CrossRef]

A. E. Siegman, “Unstable optical resonators for laser applications,” Proc. IEEE, vol. 53, pp. 277–287, March1965.

[CrossRef]

A. G. Fox, T. Li, “Modes in a maser interferometer with curved and tilted mirrors,” Proc. IEEE, vol. 51, pp. 80–89, January1963.

[CrossRef]

H. Kogelnik, W. W. Rigrod, “Visual display of isolated optical-resonator modes,” Proc. IRE (Correspondence), vol. 50, p. 220, February1962.

A. G. Fox, T. Li, “Resonant modes in an optical maser,” Proc. IRE(Correspondence), vol. 48, pp. 1904–1905, November1960; “Resonant modes in a maser interferometer,” Bell Sys. Tech. J., vol. 40, pp. 453–488, March1961.

J. R. Pierce, “Modes in sequences of lenses,” Proc. Nat’l Acad. Sci., vol. 47, pp. 1808–1813, November1961.

H. Hochstadt, “On the eigenvalue of a class of integral equations arising in laser theory,” SIAM Rev., vol. 8, pp. 62–65, January1966.

[CrossRef]

R. H. Dicke, “Molecular amplification and generation systems and methods,” U. S. Patent2 851 652, September9, 1958.

A. G. Fox, T. Li, to be published.

J. C. Heurtley, “Hyperspheroidal functions—optical resonators with circular mirrors,” in Proc. Symposium on Quasi-Optics. New York: Polytechnic Press, 1964, pp. 367–375.

G. Goubau, “Optical relations for coherent wave beams,” in Electromagnetic Theory and Antennas. New York: Macmillan, 1963, pp. 907–918.

W. Brower, Matrix Methods in Optical Instrument Design. New York: Benjamin, 1964. E. L. O’Neill, Introduction to Statistical Optics. Reading, Mass.: Addison-Wesley, 1963.

G. A. Deschamps, P. E. Mast, “Beam tracing and applications,” in Proc. Symposium on Quasi-Optics. New York: Polytechnic Press, 1964, pp. 379–395.

J. R. Pierce, Theory and Design of Electron Beams. New York: Van Nostrand, 1954, p. 194.

F. B. Hildebrand, Methods of Applied Mathematics. Englewood Cliffs, N. J.: Prentice Hall, 1952, pp. 412–413.

A. G. Fox, T. Li, “Modes in a maser interferometer with curved mirrors,” in Proc. Third International Congress on Quantum Electronics. New York: Columbia University Press, 1964, pp. 1263–1270.

H. Kogelnik, “Modes in optical resonators,” in Lasers, A. K. Levine, Ed. New York: Dekker, 1966.