[1] Source: COAST 100K Coastline and State Borders database, 1993 and Geoscience Australia GEODATA TOPO-250K database.

The length measurement of coastlines are approximate only. It depends on how finely the curves and inlets of the coasts are measured and where the actual coastline is measured (eg High Water / Low Water). A coastline is known as a Fractal object. Coastlines are very irregular so as the scale of measurement decreases, the estimated length increases without limit.

[2] Source: https://www.cia.gov/library/publications/the-world-factbook/

[3] Not including Australian Antarctic Territory

[4] Source: http://www.infoplease.com/toptens/worldrivers.html