Like and unlike ; stages 1,2%3 a unit for teachers.

Xehetasun bibliografikoak
Egile korporatiboa:	Schools Council, Nuffield Foundation, Nuffield Foundation, Scottish Education Department
Formatua:	Liburua
Hizkuntza:	ingelesa
Argitaratua:	London MacDonald Educational 1973.
Saila:	Science 5/13 Project
Gaiak:	Science > Study and teaching (Elementary).