Some resources about coordinates transformation :
<ul>
	<li>C.T. Russell, (1971) "Geophysical Coordinate Transformations", Cosmic. Electrodyn. 2, 184-196</li>
	<li>M.A. Hapgood, (1992) "Space Physics Coordinate Transformations: A User Guide", Planet. Space Sci. 40, 711-717 (but see correction note in Hapgood (1997))</li>
	<li>M.A. Hapgood, (1997) "Corrigendum to Space Physics Coordinate Transformations: A User Guide", Planet. Space Sci. 45, 1047.</li>
	<li> References for Coordinate Transformations <a href="http://www.mssl.ucl.ac.uk/grid/iau/extra/local_copy/SP_coords/refs.htm" target="_blank">http://www.mssl.ucl.ac.uk/grid/iau/extra/local_copy/SP_coords/refs.htm</a></li>
	<li>M.Fraenz and D.Harper, Heliospheric Coordinate Systems, Plan. Space Sci., 50, 217-233 (Feb 2002) - Associated site: <a href="http://www.mps.mpg.de/homes/fraenz/systems/" target="_blank">http://www.mps.mpg.de/homes/fraenz/systems/</a></li>
	<li><a href="http://cdpp.eu/index.php/Scientific-libraries/maglib.html" target="_blank">MAGLIB</a></li>
	<li><a href="http://cdpp.eu/index.php/Scientific-libraries/rocotlib.html" target="_blanck">ROCOTLIB</a></li>
</ul>