Padron:Cite-NBK
"Cite-NBK". The New Book of Knowledge (Ang Bagong Aklat ng Kaalaman), Grolier Incorporated. 1977.{{cite ensiklopedya}}
: CS1 maint: date auto-translated (link)
"Cite-NBK". The New Book of Knowledge (Ang Bagong Aklat ng Kaalaman), Grolier Incorporated. 1977.{{cite ensiklopedya}}
: CS1 maint: date auto-translated (link)