Frnman, N., & Frnman, P. O. (1965). JWKB approximation: Contributions to the theory. North-Holland Publishing.
Lua i Stíl Chicago (17ú heag.)Frnman, Nanny, agus Per Olof Frnman. JWKB Approximation: Contributions to the Theory. Amsterdam: North-Holland Publishing, 1965.
Lua MLA (9ú heag.)Frnman, Nanny, agus Per Olof Frnman. JWKB Approximation: Contributions to the Theory. North-Holland Publishing, 1965.
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