| Ion-acoustic waves at the night side of Titan’s ionosphere: higher-order approximation | 
| S M Ahmed,E R Hassib,U M Abdelsalam,R E Tolba,W M Moslem | 
| Figure 1. The phase velocity λ versus the density ratio N2, where μ2 = 0.97, μ3 = 0.68, σ1,2,3 = 0.1, and N3 = 0.1. | 
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