APA (7th ed.) Citation
(1989). XXVI Colloguium Spectroscopicum Internationale Volume IV.
Chicago Style (17th ed.) Citation
XXVI Colloguium Spectroscopicum Internationale Volume IV. Sofia, 1989.
MLA (9th ed.) Citation
XXVI Colloguium Spectroscopicum Internationale Volume IV. 1989.
Warning: These citations may not always be 100% accurate.