Articles and reference material
The Station Cancellations of Tasmanian Railway Parcel Stamps by Dr Owen Ingles discusses the use of railway station cancellers from 1917 to 1977. The article first appeard in The courier, Revenues special edition, 2003.
Tasmanian Numerals on Pictorials by Hugh Freeman provides the background and valuable reference material regarding the Barred Numeral cancellations on Pictorial stamps. It was published in The Courier No 28, Special Edition on Tasmanian Pictorials 1999.