+Helena's PhD thesis ref

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@41267 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.slope.aspect/r.slope.aspect.html

@@ -161,6 +161,8 @@ aspect is computed. The aspect for all cells with slope <
 <ul>
 <li> Horn, B. K. P. (1981). <i>Hill Shading and the Reflectance Map</i>, Proceedings
 of the IEEE, 69(1):14-47.
+<li> Mitasova, H. (1985). <i>Cartographic aspects of computer surface modeling. PhD thesis.</i>
+Slovak Technical University , Bratislava
 <li> Hofierka, J., Mitasova, H., Neteler, M., 2009. <i>Geomorphometry in GRASS GIS.</i>
 In: Hengl, T. and Reuter, H.I. (Eds), <i>Geomorphometry: Concepts, Software, Applications. </i>
 Developments in Soil Science, vol. 33, Elsevier, 387-410 pp,