Dergiler / International Electronic Journal of Geometry / 2018 / Cilt: 11 - Sayı: 2A δ-Invariant for QR-Submanifolds in Quaternion Space FormsGabriel MACSİM, Adela MİHAİDergiInternational Electronic Journal of GeometrySayı2018 · Cilt: 11 - Sayı: 2Sayfa8–17DOI—