Theory and practice in the elementary school.
| Egile nagusia: | |
|---|---|
| Formatua: | Liburua | 
| Argitaratua: | New York
          The McMillan Co.
    
        c1951. | 
| Egile nagusia: | |
|---|---|
| Formatua: | Liburua | 
| Argitaratua: | New York
          The McMillan Co.
    
        c1951. |