Fabra, Norberto F.
Trigonometry for secondary schools / Norberto F. Fabra. - Rev. ed. - Las Pinas, MM : Fabra N.F. Educational Books, 1994. - viii, 296 p. : ill.
Trigonometry--Study and teaching (Secondary)
Trigonometry for secondary schools / Norberto F. Fabra. - Rev. ed. - Las Pinas, MM : Fabra N.F. Educational Books, 1994. - viii, 296 p. : ill.
Trigonometry--Study and teaching (Secondary)