TY - BOOK ID - 129416861 TI - International Comparisons of R&D Expenditure: Does an R&D PPP Make a Difference? PY - 2007 PB - Cambridge, Mass. National Bureau of Economic Research DB - UniCat UR - https://www.unicat.be/uniCat?func=search&query=sysid:129416861 AB - ER -