・Corrected a misprint in the Introduction ("from point of view" ---> "from the point of view")

・Added the reference [pTchIn] to the Bibliography, together with a reference to [pTchIn] in \S 3.3, (ii)

・In \S 3.7, (i), and \S 3.7, (ii), (10^{est}), added a reference to [IUTchIII], Remark 3.11.1

・Slightly modified the wording at the beginning of \S 3.9

・Added \S 3.10

・Added the references [NodNon], [CbTpII], [MT], [CombCusp], [MlWd] to the Bibliography