Marginally stable orbits around Maclaurin spheroids and low-mass quark stars P. Amsterdamski, T. Bulik, D. Gondek-Rosińska and W. Kluźniak A&A, 381 1 (2002) L21-L24 Published online: 15 January 2002 DOI: 10.1051/0004-6361:20011555