Sapngad, Johnny I.  <br/><br/>
Growth and yield performance of sweet potato (PSB SP 15) applied with different NPK levels under San Manuel soil series 
Johnny I. Sapngad  
 -  2004 
 - xiv, 50 leaves   28 cm.  
<br/><br/> Thesis (BS Agriculture-Soil Science) -- Mariano Marcos State University-College of Agriculture, Food & Sustainable Development, Batac City  
<br/><br/>Bibliography: leaves 29-30