Exchange Relation in sl3 WZNW model in Semiclassical Limit

We consider the exchange relations of screened vertex operators in the sl3 Wess-Zumino-Novikov-Witten(WZNW) model in the semiclassical limit (where level k tends to infinity). We demonstrate that the coefficients of the exchange relations of the screened vertex operators coincide with the ones of the spider diagrams. The spider diagrams are composed of 3-point vertices, and differ from ordinary string diagrams.