Period changes in W UMa-type eclipsing binaries: DK Cygni, V401 Cygni, AD Phoenicis and Y Sextantis
Astron. Astrophys. Suppl. Ser., 147 2 (2000) 243-249
Published online: 15 December 2000
DOI: 10.1051/aas:2000300