Reference Library - Floatation Density
The links below to references in the literature which include analytical aspects of philately. These may be very important because the name of books and papers are often not indicative of details of their contents.
|Liston, Edward M.||The "China Clay" Variety of the 1908-1910 Washington-Franklin Issue?||Collectors Club Philatelist, Vol. 84(2)2005. pp. 105-112|