What is the best source for historical ratios (such as p/e, p/s, price/book, dividend yield) of various international stock indexes (e.g.
FTSE EPRA/NAREIT Developed Asia or
I found a possible data source. It offers fundamentals i.e. the accounting ratios you listed (P/E, dividend yield, price/book) for international stock indexes.
International equity indices based on EAFE definitions are maintained by Professor French of French-Fama fame, at Dartmouth's Tuck Business School website. Specifics of methodology, and countries covered is available here. MSCI is the data source. Historical time interval for most countries is from 1975 onward. (Singapore was one of the countries included).
Obtaining historical ratios for international stock indices is not easily found for free. Your question didn't specify free though. If that is not a constraint, you may wish to check the MSCI Barra international stock indices also.