Expert appraisal and research, advice on flower, still-life paintings and drawings, particularly Dutch works of the 17th and 18th centuries. Experience is based on research and data collection, mainly performed over a period of more than 30 years on a corpus exceeding 30,000 artworks, reproduction files and documentation. This collection of photography and files is believed to be the largest and best organized on this subject in the world, encompassing an extensive library containing many sources from the sixteenth century until the present.