Friedrich Heinrich Albert Wangerin
... that German mathematician Friedrich Heinrich Albert Wangerin wrote an important two-volume treatise on potential theory and spherical functions in 1909 and 1921?
... that <a href="./Germany" id="mwCCg" rel="mw:WikiLink" title="Germany">German</a> <a href="./Mathematician" id="mwCCk" rel="mw:WikiLink" title="Mathematician">mathematician</a> <b id="mwCCo"><a href="./Friedrich_Heinrich_Albert_Wangerin" id="mwCCs" rel="mw:WikiLink" title="Friedrich Heinrich Albert Wangerin">Friedrich Heinrich Albert Wangerin</a></b> wrote an important two-volume treatise on <a href="./Potential_theory" id="mwCCw" rel="mw:WikiLink" title="Potential theory">potential theory</a> and <a class="mw-redirect" href="./Spherical_functions" id="mwCC0" rel="mw:WikiLink" title="Spherical functions">spherical functions</a> in 1909 and 1921?