This is a list of philatelists, persons notable for their contributions to philately. Though worthless as postage, they became popular with philatelists and oddity collectors. In addition, San Marino sells collectible postage stamps to philatelists. Philatelists traditionally use names to identify postage stamp colors. This is why Colombian stamps are nowadays very scarce and of great interest to philatelists. Turkey's stamps also have a complex history of overprints of interest to philatelists. The province is remembered today by philatelists for having issued postage stamps from 1880 on. The company issued a number of telegraph stamps which are of interest to philatelists. The lighter stamps were named "vermilion" by philatelists. Collecting such cancellations is a pastime of many philatelists and postal history researchers. Those who produce counterfeits appeal to a very different market from philatelists. A number of philatelists have published studies of the forgeries of Turkey. Such markings are known as "Karin Grech crosses" by philatelists. She was also one of the first female philatelists in Russia. George V was one of the notable philatelists of his day.