In order to combine theory with practice to solve purchasing management problems of lz manufacture which is a research object in the paper and provide references for other similar enterprises , purchasing management for lz manufacture is studied by the way of theory and demonstration .
Others say his lubrizol ( lz , fortune 500 ) share purchases were not illegal , but certainly displayed poor judgment by the man most often mentioned in the press as buffett 's heir apparent .
Buffett later got around to mentioning in that letter the rather daunting fact that he had learned sokol recommended berkshire acquire lubricants maker lubrizol ( lz ) without disclosing his purchase of the company 's shares .