Phase-shift versus amplitude-ratio diagram for the frequency of 21 d^-1 and a non-rotating model with M = 1.55 M_⊙, α_ML = 0.5, and d_ov = 0.2. Each box corresponds to a measure with its own uncertainties following the legend; band y is the reference. Every symbol (o, +, ∗, Δ) represents an ℓ degree (0, 1, 2, and 3, respectively).