More discussion of the terminology of alternating current power

In the the paper by D.W. Knudsen, "Further Discussion of the Terminology of Alternating Current Power" (see ibid., vol.19, no.3, p.72, 1999), there was a discussion of the convention used to describe reactive power caused by a lagging current. In the European source cited, the convention used was to describe this power as negative. The points to two American references that discuss this convention. The author also points to another reference that indirectly discusses this convention.