A. V. Buryak, P. Di Trapani, D. V. Skryabin, and S. Trillo, “Optical solitons due to quadratic nonlinearities: from basic physics to futuristic applications,” Phys. Rep. 370, 63–235 (2002).

[CrossRef]

C. Conti, S. Trillo, P. Di Trapani, J. Kilius, A. Bramati, S. Minardi, W. Chinaglia, and G. Valiulis, “Effective lensing effects in parametric frequency conversion,” J. Opt. Soc. Am. B 19, 852–859 (2002).

[CrossRef]

P. Di Trapani, A. Bramati, S. Minardi, W. Chinaglia, C. Conti, S. Trillo, J. Kilius, and G. Valiulis, “Focusing versus defocusing nonlinearities due to parametric wave mixing,” Phys. Rev. Lett. 87, 183902 (2001).

[CrossRef]

V. Couderc, E. Lopez Lago, C. Simos, and A. Barthelemy, “Experiments in quadratic soliton generation and steering in a noncollinear geometry,” Opt. Lett. 26, 905–907 (2001).

[CrossRef]

X. Liu, K. Beckwitt, and F. W. Wise, “Noncollinear generation of optical spatio-temporal solitons and application to ultra-fast digital logic,” Phys. Rev. E 61, R4722–R4725 (2000).

[CrossRef]

M. R. Belié, A. Stepken, and F. Kaiser, “Spiraling behavior of photorefractive screening solitons,” Phys. Rev. Lett. 82, 544–547 (1999).

[CrossRef]

V. Buryak and V. V. Steblina, “Soliton collisions in bulk quadratic media: comprehensive analytical and numerical study,” J. Opt. Soc. Am. B 16, 245–255 (1999).

[CrossRef]

A. V. Buryak, Yu. S. Kivshar, M.-f. Shih, and M. Segev, “Induced coherence and stable soliton spiraling,” Phys. Rev. Lett. 82, 81–84 (1999).

[CrossRef]

V. V. Steblina, Yu. S. Kivshar, and A. V. Buryak, “Scattering and spiraling of solitons in a bulk quadratic medium,” Opt. Lett. 23, 156–158 (1998).

[CrossRef]

M. Segev and G. I. Stegeman, “Self-trapping of optical beams: spatial solitons,” Phys. Today 51(8), 42–48 (1998).

[CrossRef]

B. Costantini, C. De Angelis, A. Barthelemy, B. Bourliaguet, and V. Kermene, “Collisions between type II two-dimensional quadratic solitons,” Opt. Lett. 23, 424–426 (1998).

[CrossRef]

R. Schiek, Y. Baek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic soliton-like beams,” Opt. Quantum Electron. 30, 861–879 (1998).

[CrossRef]

G. Leo and G. Assanto, “Collisional interactions of vectorial spatial solitary waves in type II frequency-doubling crystal,” J. Opt. Soc. Am. B 14, 3151–3161 (1997).

[CrossRef]

A. V. Buryak, Yu. S. Kivshar, and S. Trillo, “Parametric spatial solitary waves due to type-II second harmonic generation,” J. Opt. Soc. Am. B 14, 3110–3118 (1997).

[CrossRef]

Y. Baek, R. Schiek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic solitons,” Opt. Lett. 22, 1550–1552 (1997).

[CrossRef]

M.-F. Shih and M. Segev, “Three dimensional spiraling of interacting spatial solitons,” Phys. Rev. Lett. 78, 13–16 (1997).

[CrossRef]

W. Torruellas, Z. Wang, D. J. Hagan, E. W. Van Stryland, G. I. Stegeman, L. Torner, and C. R. Menyuk, “Observation of two-dimensional spatial solitary waves in a quadratic medium,” Phys. Rev. Lett. 74, 5036–5039 (1995).

[CrossRef]
[PubMed]

M. Segev, B. Crosignani, A. Yariv, and B. Fisher, “Spatial soliton on photorepractive media,” Phys. Rev. Lett. 68, 923–926 (1992).

[CrossRef]
[PubMed]

K. A. Gorshkov and L. A. Ostrovsky, “Interactions of solitons in nonintegrable systems: direct perturbation method and applications,” Physica D 3, 428–438 (1981).

[CrossRef]

V. I. Karpman and V. V. Solov’ev, “A perturbational approach to the two-soliton systems,” Physica D 3, 487–502 (1981).

[CrossRef]

R. Schiek, Y. Baek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic soliton-like beams,” Opt. Quantum Electron. 30, 861–879 (1998).

[CrossRef]

Y. Baek, R. Schiek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic solitons,” Opt. Lett. 22, 1550–1552 (1997).

[CrossRef]

V. Couderc, E. Lopez Lago, C. Simos, and A. Barthelemy, “Experiments in quadratic soliton generation and steering in a noncollinear geometry,” Opt. Lett. 26, 905–907 (2001).

[CrossRef]

B. Costantini, C. De Angelis, A. Barthelemy, B. Bourliaguet, and V. Kermene, “Collisions between type II two-dimensional quadratic solitons,” Opt. Lett. 23, 424–426 (1998).

[CrossRef]

R. Schiek, Y. Baek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic soliton-like beams,” Opt. Quantum Electron. 30, 861–879 (1998).

[CrossRef]

Y. Baek, R. Schiek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic solitons,” Opt. Lett. 22, 1550–1552 (1997).

[CrossRef]

X. Liu, K. Beckwitt, and F. W. Wise, “Noncollinear generation of optical spatio-temporal solitons and application to ultra-fast digital logic,” Phys. Rev. E 61, R4722–R4725 (2000).

[CrossRef]

M. R. Belié, A. Stepken, and F. Kaiser, “Spiraling behavior of photorefractive screening solitons,” Phys. Rev. Lett. 82, 544–547 (1999).

[CrossRef]

C. Conti, S. Trillo, P. Di Trapani, J. Kilius, A. Bramati, S. Minardi, W. Chinaglia, and G. Valiulis, “Effective lensing effects in parametric frequency conversion,” J. Opt. Soc. Am. B 19, 852–859 (2002).

[CrossRef]

P. Di Trapani, A. Bramati, S. Minardi, W. Chinaglia, C. Conti, S. Trillo, J. Kilius, and G. Valiulis, “Focusing versus defocusing nonlinearities due to parametric wave mixing,” Phys. Rev. Lett. 87, 183902 (2001).

[CrossRef]

A. V. Buryak, P. Di Trapani, D. V. Skryabin, and S. Trillo, “Optical solitons due to quadratic nonlinearities: from basic physics to futuristic applications,” Phys. Rep. 370, 63–235 (2002).

[CrossRef]

A. V. Buryak, Yu. S. Kivshar, M.-f. Shih, and M. Segev, “Induced coherence and stable soliton spiraling,” Phys. Rev. Lett. 82, 81–84 (1999).

[CrossRef]

V. V. Steblina, Yu. S. Kivshar, and A. V. Buryak, “Scattering and spiraling of solitons in a bulk quadratic medium,” Opt. Lett. 23, 156–158 (1998).

[CrossRef]

A. V. Buryak, Yu. S. Kivshar, and S. Trillo, “Parametric spatial solitary waves due to type-II second harmonic generation,” J. Opt. Soc. Am. B 14, 3110–3118 (1997).

[CrossRef]

C. Conti, S. Trillo, P. Di Trapani, J. Kilius, A. Bramati, S. Minardi, W. Chinaglia, and G. Valiulis, “Effective lensing effects in parametric frequency conversion,” J. Opt. Soc. Am. B 19, 852–859 (2002).

[CrossRef]

P. Di Trapani, A. Bramati, S. Minardi, W. Chinaglia, C. Conti, S. Trillo, J. Kilius, and G. Valiulis, “Focusing versus defocusing nonlinearities due to parametric wave mixing,” Phys. Rev. Lett. 87, 183902 (2001).

[CrossRef]

C. Conti, S. Trillo, P. Di Trapani, J. Kilius, A. Bramati, S. Minardi, W. Chinaglia, and G. Valiulis, “Effective lensing effects in parametric frequency conversion,” J. Opt. Soc. Am. B 19, 852–859 (2002).

[CrossRef]

P. Di Trapani, A. Bramati, S. Minardi, W. Chinaglia, C. Conti, S. Trillo, J. Kilius, and G. Valiulis, “Focusing versus defocusing nonlinearities due to parametric wave mixing,” Phys. Rev. Lett. 87, 183902 (2001).

[CrossRef]

M. Segev, B. Crosignani, A. Yariv, and B. Fisher, “Spatial soliton on photorepractive media,” Phys. Rev. Lett. 68, 923–926 (1992).

[CrossRef]
[PubMed]

A. V. Buryak, P. Di Trapani, D. V. Skryabin, and S. Trillo, “Optical solitons due to quadratic nonlinearities: from basic physics to futuristic applications,” Phys. Rep. 370, 63–235 (2002).

[CrossRef]

C. Conti, S. Trillo, P. Di Trapani, J. Kilius, A. Bramati, S. Minardi, W. Chinaglia, and G. Valiulis, “Effective lensing effects in parametric frequency conversion,” J. Opt. Soc. Am. B 19, 852–859 (2002).

[CrossRef]

P. Di Trapani, A. Bramati, S. Minardi, W. Chinaglia, C. Conti, S. Trillo, J. Kilius, and G. Valiulis, “Focusing versus defocusing nonlinearities due to parametric wave mixing,” Phys. Rev. Lett. 87, 183902 (2001).

[CrossRef]

M. Segev, B. Crosignani, A. Yariv, and B. Fisher, “Spatial soliton on photorepractive media,” Phys. Rev. Lett. 68, 923–926 (1992).

[CrossRef]
[PubMed]

K. A. Gorshkov and L. A. Ostrovsky, “Interactions of solitons in nonintegrable systems: direct perturbation method and applications,” Physica D 3, 428–438 (1981).

[CrossRef]

W. Torruellas, Z. Wang, D. J. Hagan, E. W. Van Stryland, G. I. Stegeman, L. Torner, and C. R. Menyuk, “Observation of two-dimensional spatial solitary waves in a quadratic medium,” Phys. Rev. Lett. 74, 5036–5039 (1995).

[CrossRef]
[PubMed]

M. R. Belié, A. Stepken, and F. Kaiser, “Spiraling behavior of photorefractive screening solitons,” Phys. Rev. Lett. 82, 544–547 (1999).

[CrossRef]

V. I. Karpman and V. V. Solov’ev, “A perturbational approach to the two-soliton systems,” Physica D 3, 487–502 (1981).

[CrossRef]

C. Conti, S. Trillo, P. Di Trapani, J. Kilius, A. Bramati, S. Minardi, W. Chinaglia, and G. Valiulis, “Effective lensing effects in parametric frequency conversion,” J. Opt. Soc. Am. B 19, 852–859 (2002).

[CrossRef]

P. Di Trapani, A. Bramati, S. Minardi, W. Chinaglia, C. Conti, S. Trillo, J. Kilius, and G. Valiulis, “Focusing versus defocusing nonlinearities due to parametric wave mixing,” Phys. Rev. Lett. 87, 183902 (2001).

[CrossRef]

A. V. Buryak, Yu. S. Kivshar, M.-f. Shih, and M. Segev, “Induced coherence and stable soliton spiraling,” Phys. Rev. Lett. 82, 81–84 (1999).

[CrossRef]

V. V. Steblina, Yu. S. Kivshar, and A. V. Buryak, “Scattering and spiraling of solitons in a bulk quadratic medium,” Opt. Lett. 23, 156–158 (1998).

[CrossRef]

A. V. Buryak, Yu. S. Kivshar, and S. Trillo, “Parametric spatial solitary waves due to type-II second harmonic generation,” J. Opt. Soc. Am. B 14, 3110–3118 (1997).

[CrossRef]

X. Liu, K. Beckwitt, and F. W. Wise, “Noncollinear generation of optical spatio-temporal solitons and application to ultra-fast digital logic,” Phys. Rev. E 61, R4722–R4725 (2000).

[CrossRef]

W. Torruellas, Z. Wang, D. J. Hagan, E. W. Van Stryland, G. I. Stegeman, L. Torner, and C. R. Menyuk, “Observation of two-dimensional spatial solitary waves in a quadratic medium,” Phys. Rev. Lett. 74, 5036–5039 (1995).

[CrossRef]
[PubMed]

C. Conti, S. Trillo, P. Di Trapani, J. Kilius, A. Bramati, S. Minardi, W. Chinaglia, and G. Valiulis, “Effective lensing effects in parametric frequency conversion,” J. Opt. Soc. Am. B 19, 852–859 (2002).

[CrossRef]

P. Di Trapani, A. Bramati, S. Minardi, W. Chinaglia, C. Conti, S. Trillo, J. Kilius, and G. Valiulis, “Focusing versus defocusing nonlinearities due to parametric wave mixing,” Phys. Rev. Lett. 87, 183902 (2001).

[CrossRef]

K. A. Gorshkov and L. A. Ostrovsky, “Interactions of solitons in nonintegrable systems: direct perturbation method and applications,” Physica D 3, 428–438 (1981).

[CrossRef]

R. Schiek, Y. Baek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic soliton-like beams,” Opt. Quantum Electron. 30, 861–879 (1998).

[CrossRef]

Y. Baek, R. Schiek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic solitons,” Opt. Lett. 22, 1550–1552 (1997).

[CrossRef]

A. V. Buryak, Yu. S. Kivshar, M.-f. Shih, and M. Segev, “Induced coherence and stable soliton spiraling,” Phys. Rev. Lett. 82, 81–84 (1999).

[CrossRef]

M. Segev and G. I. Stegeman, “Self-trapping of optical beams: spatial solitons,” Phys. Today 51(8), 42–48 (1998).

[CrossRef]

M.-F. Shih and M. Segev, “Three dimensional spiraling of interacting spatial solitons,” Phys. Rev. Lett. 78, 13–16 (1997).

[CrossRef]

M. Segev, B. Crosignani, A. Yariv, and B. Fisher, “Spatial soliton on photorepractive media,” Phys. Rev. Lett. 68, 923–926 (1992).

[CrossRef]
[PubMed]

A. V. Buryak, Yu. S. Kivshar, M.-f. Shih, and M. Segev, “Induced coherence and stable soliton spiraling,” Phys. Rev. Lett. 82, 81–84 (1999).

[CrossRef]

M.-F. Shih and M. Segev, “Three dimensional spiraling of interacting spatial solitons,” Phys. Rev. Lett. 78, 13–16 (1997).

[CrossRef]

A. V. Buryak, P. Di Trapani, D. V. Skryabin, and S. Trillo, “Optical solitons due to quadratic nonlinearities: from basic physics to futuristic applications,” Phys. Rep. 370, 63–235 (2002).

[CrossRef]

R. Schiek, Y. Baek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic soliton-like beams,” Opt. Quantum Electron. 30, 861–879 (1998).

[CrossRef]

Y. Baek, R. Schiek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic solitons,” Opt. Lett. 22, 1550–1552 (1997).

[CrossRef]

V. I. Karpman and V. V. Solov’ev, “A perturbational approach to the two-soliton systems,” Physica D 3, 487–502 (1981).

[CrossRef]

M. Segev and G. I. Stegeman, “Self-trapping of optical beams: spatial solitons,” Phys. Today 51(8), 42–48 (1998).

[CrossRef]

R. Schiek, Y. Baek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic soliton-like beams,” Opt. Quantum Electron. 30, 861–879 (1998).

[CrossRef]

Y. Baek, R. Schiek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic solitons,” Opt. Lett. 22, 1550–1552 (1997).

[CrossRef]

W. Torruellas, Z. Wang, D. J. Hagan, E. W. Van Stryland, G. I. Stegeman, L. Torner, and C. R. Menyuk, “Observation of two-dimensional spatial solitary waves in a quadratic medium,” Phys. Rev. Lett. 74, 5036–5039 (1995).

[CrossRef]
[PubMed]

M. R. Belié, A. Stepken, and F. Kaiser, “Spiraling behavior of photorefractive screening solitons,” Phys. Rev. Lett. 82, 544–547 (1999).

[CrossRef]

W. Torruellas, Z. Wang, D. J. Hagan, E. W. Van Stryland, G. I. Stegeman, L. Torner, and C. R. Menyuk, “Observation of two-dimensional spatial solitary waves in a quadratic medium,” Phys. Rev. Lett. 74, 5036–5039 (1995).

[CrossRef]
[PubMed]

W. Torruellas, Z. Wang, D. J. Hagan, E. W. Van Stryland, G. I. Stegeman, L. Torner, and C. R. Menyuk, “Observation of two-dimensional spatial solitary waves in a quadratic medium,” Phys. Rev. Lett. 74, 5036–5039 (1995).

[CrossRef]
[PubMed]

A. V. Buryak, P. Di Trapani, D. V. Skryabin, and S. Trillo, “Optical solitons due to quadratic nonlinearities: from basic physics to futuristic applications,” Phys. Rep. 370, 63–235 (2002).

[CrossRef]

C. Conti, S. Trillo, P. Di Trapani, J. Kilius, A. Bramati, S. Minardi, W. Chinaglia, and G. Valiulis, “Effective lensing effects in parametric frequency conversion,” J. Opt. Soc. Am. B 19, 852–859 (2002).

[CrossRef]

P. Di Trapani, A. Bramati, S. Minardi, W. Chinaglia, C. Conti, S. Trillo, J. Kilius, and G. Valiulis, “Focusing versus defocusing nonlinearities due to parametric wave mixing,” Phys. Rev. Lett. 87, 183902 (2001).

[CrossRef]

A. V. Buryak, Yu. S. Kivshar, and S. Trillo, “Parametric spatial solitary waves due to type-II second harmonic generation,” J. Opt. Soc. Am. B 14, 3110–3118 (1997).

[CrossRef]

C. Conti, S. Trillo, P. Di Trapani, J. Kilius, A. Bramati, S. Minardi, W. Chinaglia, and G. Valiulis, “Effective lensing effects in parametric frequency conversion,” J. Opt. Soc. Am. B 19, 852–859 (2002).

[CrossRef]

P. Di Trapani, A. Bramati, S. Minardi, W. Chinaglia, C. Conti, S. Trillo, J. Kilius, and G. Valiulis, “Focusing versus defocusing nonlinearities due to parametric wave mixing,” Phys. Rev. Lett. 87, 183902 (2001).

[CrossRef]

W. Torruellas, Z. Wang, D. J. Hagan, E. W. Van Stryland, G. I. Stegeman, L. Torner, and C. R. Menyuk, “Observation of two-dimensional spatial solitary waves in a quadratic medium,” Phys. Rev. Lett. 74, 5036–5039 (1995).

[CrossRef]
[PubMed]

W. Torruellas, Z. Wang, D. J. Hagan, E. W. Van Stryland, G. I. Stegeman, L. Torner, and C. R. Menyuk, “Observation of two-dimensional spatial solitary waves in a quadratic medium,” Phys. Rev. Lett. 74, 5036–5039 (1995).

[CrossRef]
[PubMed]

X. Liu, K. Beckwitt, and F. W. Wise, “Noncollinear generation of optical spatio-temporal solitons and application to ultra-fast digital logic,” Phys. Rev. E 61, R4722–R4725 (2000).

[CrossRef]

M. Segev, B. Crosignani, A. Yariv, and B. Fisher, “Spatial soliton on photorepractive media,” Phys. Rev. Lett. 68, 923–926 (1992).

[CrossRef]
[PubMed]

V. Buryak and V. V. Steblina, “Soliton collisions in bulk quadratic media: comprehensive analytical and numerical study,” J. Opt. Soc. Am. B 16, 245–255 (1999).

[CrossRef]

G. Leo and G. Assanto, “Collisional interactions of vectorial spatial solitary waves in type II frequency-doubling crystal,” J. Opt. Soc. Am. B 14, 3151–3161 (1997).

[CrossRef]

A. V. Buryak, Yu. S. Kivshar, and S. Trillo, “Parametric spatial solitary waves due to type-II second harmonic generation,” J. Opt. Soc. Am. B 14, 3110–3118 (1997).

[CrossRef]

C. Conti, S. Trillo, P. Di Trapani, J. Kilius, A. Bramati, S. Minardi, W. Chinaglia, and G. Valiulis, “Effective lensing effects in parametric frequency conversion,” J. Opt. Soc. Am. B 19, 852–859 (2002).

[CrossRef]

Y. Baek, R. Schiek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic solitons,” Opt. Lett. 22, 1550–1552 (1997).

[CrossRef]

B. Costantini, C. De Angelis, A. Barthelemy, B. Bourliaguet, and V. Kermene, “Collisions between type II two-dimensional quadratic solitons,” Opt. Lett. 23, 424–426 (1998).

[CrossRef]

V. Couderc, E. Lopez Lago, C. Simos, and A. Barthelemy, “Experiments in quadratic soliton generation and steering in a noncollinear geometry,” Opt. Lett. 26, 905–907 (2001).

[CrossRef]

V. V. Steblina, Yu. S. Kivshar, and A. V. Buryak, “Scattering and spiraling of solitons in a bulk quadratic medium,” Opt. Lett. 23, 156–158 (1998).

[CrossRef]

R. Schiek, Y. Baek, G. I. Stegeman, I. Baumann, and W. Sohler, “Interactions between one-dimensional quadratic soliton-like beams,” Opt. Quantum Electron. 30, 861–879 (1998).

[CrossRef]

A. V. Buryak, P. Di Trapani, D. V. Skryabin, and S. Trillo, “Optical solitons due to quadratic nonlinearities: from basic physics to futuristic applications,” Phys. Rep. 370, 63–235 (2002).

[CrossRef]

X. Liu, K. Beckwitt, and F. W. Wise, “Noncollinear generation of optical spatio-temporal solitons and application to ultra-fast digital logic,” Phys. Rev. E 61, R4722–R4725 (2000).

[CrossRef]

M. R. Belié, A. Stepken, and F. Kaiser, “Spiraling behavior of photorefractive screening solitons,” Phys. Rev. Lett. 82, 544–547 (1999).

[CrossRef]

P. Di Trapani, A. Bramati, S. Minardi, W. Chinaglia, C. Conti, S. Trillo, J. Kilius, and G. Valiulis, “Focusing versus defocusing nonlinearities due to parametric wave mixing,” Phys. Rev. Lett. 87, 183902 (2001).

[CrossRef]

M. Segev, B. Crosignani, A. Yariv, and B. Fisher, “Spatial soliton on photorepractive media,” Phys. Rev. Lett. 68, 923–926 (1992).

[CrossRef]
[PubMed]

A. V. Buryak, Yu. S. Kivshar, M.-f. Shih, and M. Segev, “Induced coherence and stable soliton spiraling,” Phys. Rev. Lett. 82, 81–84 (1999).

[CrossRef]

W. Torruellas, Z. Wang, D. J. Hagan, E. W. Van Stryland, G. I. Stegeman, L. Torner, and C. R. Menyuk, “Observation of two-dimensional spatial solitary waves in a quadratic medium,” Phys. Rev. Lett. 74, 5036–5039 (1995).

[CrossRef]
[PubMed]

M.-F. Shih and M. Segev, “Three dimensional spiraling of interacting spatial solitons,” Phys. Rev. Lett. 78, 13–16 (1997).

[CrossRef]

M. Segev and G. I. Stegeman, “Self-trapping of optical beams: spatial solitons,” Phys. Today 51(8), 42–48 (1998).

[CrossRef]

K. A. Gorshkov and L. A. Ostrovsky, “Interactions of solitons in nonintegrable systems: direct perturbation method and applications,” Physica D 3, 428–438 (1981).

[CrossRef]

V. I. Karpman and V. V. Solov’ev, “A perturbational approach to the two-soliton systems,” Physica D 3, 487–502 (1981).

[CrossRef]

M. Toda, Nonlinear Waves and Solitons (Kluwer Academic, Boston, Mass., 1990).