Erdem, A. Et Al. 2007. Orbital period variations of four Algol-type eclipsing binaries: SW Cyg, UU Leo, XX Cep and BO Vul. ASTRONOMISCHE NACHRICHTEN , vol.328, no.6 , 543-550.

Erdem, A., Dogru, S. S., Bakis, V., & Demircan, O., (2007). Orbital period variations of four Algol-type eclipsing binaries: SW Cyg, UU Leo, XX Cep and BO Vul. ASTRONOMISCHE NACHRICHTEN , vol.328, no.6, 543-550.

Erdem, Ahmet Et Al. "Orbital period variations of four Algol-type eclipsing binaries: SW Cyg, UU Leo, XX Cep and BO Vul," ASTRONOMISCHE NACHRICHTEN , vol.328, no.6, 543-550, 2007

Erdem, Ahmet Et Al. "Orbital period variations of four Algol-type eclipsing binaries: SW Cyg, UU Leo, XX Cep and BO Vul." ASTRONOMISCHE NACHRICHTEN , vol.328, no.6, pp.543-550, 2007

Erdem, A. Et Al. (2007) . "Orbital period variations of four Algol-type eclipsing binaries: SW Cyg, UU Leo, XX Cep and BO Vul." ASTRONOMISCHE NACHRICHTEN , vol.328, no.6, pp.543-550.

@article{article, author={Ahmet Erdem Et Al. }, title={Orbital period variations of four Algol-type eclipsing binaries: SW Cyg, UU Leo, XX Cep and BO Vul}, journal={ASTRONOMISCHE NACHRICHTEN}, year=2007, pages={543-550} }