APA (7th ed.) Citation

Wong, K. P., & Yu, P. C. (1998). Upper-air normals for Hong Kong, 1961-1990. Hong Kong Observatory.

Chicago Style (17th ed.) Citation

Wong, K. P., and P. C. Yu. Upper-air Normals for Hong Kong, 1961-1990. Hong Kong: Hong Kong Observatory, 1998.

MLA (9th ed.) Citation

Wong, K. P., and P. C. Yu. Upper-air Normals for Hong Kong, 1961-1990. Hong Kong Observatory, 1998.