translate English to French: Explanation of sketches 3-5.4.2.5.1 (a) and (b) and 3-5.4.2.5.2 (a) and (b)
Explications relatives aux figures 3-5.4.2.5.1 (a) et (b), et 3-5.4.2.5.2 (a) et (b)