He gave special attention to the gasoline tax , which was the most lucrative source of revenue in Texas .
Because of Mr. Sheppard 's active interest in tax matters , he became widely recognized as an authority in the field of tax administration .
Sheppard gave special attention to the gasoline tax , which was the most lucrative source of revenue in Texas .
Because of Mr. Sheppard 's active interest in tax matters , he became widely recognized as an authority in the field of tax administration .