Diagram of magnitude residuals of I-band P–L relation, ΔI₀, against the corresponding residuals of the P–W relation, ΔW, for F (upper left panel) and 1O (lower left panel) LMC Cepheids. Objects that deviate more than three sigma from this relation are marked with black crosses. These objects are also shown in a CMD of F (blue crosses) and 1O (red crosses) LMC Cepheids in the right panel.