APA
World Health Organization, . (1997). Determination of airborne fibre number concentrations: a recommended methods by phase-contrast optical microscopy (membrane filter method). Geneva: World Health Oraganization.
Chicago
World Health Organization, . 1997. Determination of airborne fibre number concentrations: a recommended methods by phase-contrast optical microscopy (membrane filter method). Geneva: World Health Oraganization.
Harvard
World Health Organization, . (1997). Determination of airborne fibre number concentrations: a recommended methods by phase-contrast optical microscopy (membrane filter method). Geneva: World Health Oraganization.
MLA
World Health Organization, . Determination of airborne fibre number concentrations: a recommended methods by phase-contrast optical microscopy (membrane filter method). Geneva: World Health Oraganization. 1997.