Lecturas de ciencias biológicas; escuela intermedia. 

 - [Hato Rey, P.R.]  1967. 
 - 204 p.  illus., draws. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Biology--Study and teaching (Secondary)--Addresses, essays, lectures.
<br/><br/><label>Subjects--Geographic Terms: </label><br/>Puerto Rico--Biology.