Ramirez, Mariecon G.  <br/><br/>
Research-based self-learning packages on ecological concepts 
Mariecon G. Ramirez 
 -  2001 
 - xiv, 107 leaves   28 cm. 
<br/><br/> Thesis (MA Education-Biology) -- Mariano Marcos State University-Graduate School, Laoag City  
<br/><br/>Bibliography: leaves 42-44