Here is the abstract from the article, which I can quote:
To what extent may the prayers and ceremonial actions of the usus antiquior be used in the celebration of Mass according to the Missal of Pope Paul VI? Examples of some elements being used by Archbishop Ranjith and Pope Benedict XVI seem to contradict in practice the idea that such enrichment is forbidden. An often quoted text from Notitiae, which discouraged the use of traditional elements, is examined and found wanting, especially in the light of Summorum Pontificum, which is considered in terms of its application to the celebration of the newer form of Mass. The enhancement of the newer form of Mass by the addition of elements from the usus antiquior is distinguished from arbitrary deformation of the liturgy and from the imposition of the priest’s personal whims. Some possible future practical developments are outlined.