To dial an International Number from Singapore dial 00
The expression "White Pages" is the opposite of "Yellow Pages"
Whitepages are used to find people and companies by Name
... classified in Alphabetical order
Yellowpages are used to find companies by Activity
... classified by Business Sectors
White Pages & Yellow Pages
are edited by many different Telecom Operators or Directory Publishers
mostly completely independant from each other.
Many times they are linked
to the historic Telephone Compnay of the respective Country.
The expressions "White Pages" and "Yellow Pages"
came up in the United States.