Use PA4 transitional page format (21 × 28 cm)
Use PA4 transitional page format (21 × 28 cm)

https://en.wikipedia.org/wiki/Paper_size#PA4_or_L4
Signed-off-by: Roger Sheen <a61a1add71dadc74037ae5e44ee30713db9a7451@infotexture.net>

dita-ot/docs