W.A.C.H. Dobson 
A Dictionary of the Chinese Particles [PDF ebook] 
with a prolegomenon in which the problems of the particles are considered and they are classified by their grammatical functions

This dictionary treats some 694 particles, the nuclei, as it were, of the grammar of Classical Chinese. It includes all the auxiliaries (modals, aspectuals, etc.); the markers of grammatical relationships; the conjunctions, numerals, and markers of enumeration; the substitutes (pronouns, demonstratives, and interrogative and indefinite substitutes); and the interjections and allegro forms which occur in classical literature from its beginnings top the Six Dynasties.

Copius examples of usage and currency are given and cross-references to concordances and other reference works are supplied, the whole designed to provide for the student of the Chinese language a reference work of a kind that hitherto has not existed.

In the Prolegomenon, the problems of the particles and the part they play in the grammar of Classical Chinese are considered, and the particles are classified. In the Dictionary proper, the particles are treated individually; their functions are described and illustrated by textual examples, which are translated for the convenience of the user. Following the Dictionary are a Radical Chart and Radical Index, by radical and stroke count, a table for conversion from the Wades-Giles system of romanization to the Gwoyeu Romatzyh system, and a list of characters with obscure radicals by total stroke count.