TY - GEN digital ID - 132594573 TI - The benefits and costs of head start AU - Ludwig, Jens AU - Philips, Deborah A. PY - 2007 PB - Cambridge, Mass. NBER DB - UniCat KW - Zonder onderwerpscode: economie UR - https://www.unicat.be/uniCat?func=search&query=sysid:132594573 AB - ER -