BX    And The brighter component of the visual double ADS 1671. Separation
BX    And 19.7".  Possible presence of a third body on about a 60 year orbit
BX    And seen in the (O-C) diagram.
SS    Ari Possible quadruple system. A third body is seen in the (O-C) diagram
SS    Ari on an ~44.8 years orbit. Possible fourth component on a 28 years
SS    Ari orbit.
AP    Aur Fast period increase since the beginning of the observations (1901)
AP    Aur with mean (dP/dt)/P= +2.12*10^-6^year^-1^. The (O-C) residuals
AP    Aur deviate from the parabolic representation.
44    Boo Fainter component of the visual double ADS 9494. The orbital period of
44    Boo the visual pair is 206 years. TU Boo: Abrupt period decrease
44    Boo {Delta}P/P=-1.52*10^-5^ around 1983.
TY    Boo Possible presence of a third body indicated by the sinusoidal
TY    Boo variation (P~65years) seen in the (O-C) diagram.
TZ    Boo Two abrupt period changes around 1979 ({Delta}P/P=-2.45*10^-5^) and
TZ    Boo around 1992 ({Delta}P/P=+3.27*10^-5^).
VW    Boo Secular period decrease (dP/dt)/P=-4.97*10^-7^year^-1^ since the
VW    Boo beginning of the observations (1938).
XY    Boo Fast period increase since the beginning of the observations (1944)
XY    Boo with mean (dP/dt)/P= +1.56*10^-6^year^-1^. The (O-C) residuals
XY    Boo deviate a lot from the parabolic representation.
AC    Boo Abrupt period increase {Delta}P/P=+2.32*10^-5^ around 1980.
CK    Boo Abrupt period increase {Delta}P/P=+2.0*10^-5^ around 1990.
V366  Cas Period increase since the beginning of the observations (1911) with
V366  Cas mean (dP/dt)/P=+5.27*10^-7^year^-1^. The (O-C) residuals deviate a
V366  Cas lot from the parabolic representation.
V523  Cas Presence of the third body on ~101 years seen in the (O-C) diagram.
VW    Cep The system is probably quadruple - P3=31.4 years, e3=0.771,
VW    Cep P4=18.6 years, e4=0.499.
CV    Cyg Period decrease since the beginning of the observations (1898) with
CV    Cyg mean (dP/dt)/P=-4.43*10^-7^year^-1^ or two abrupt period decreases
CV    Cyg around 1930 and 1975.
V1073 Cyg Period decrease with mean (dP/dt)/P=-4.88*10^-7^year^-1^ since the
V1073 Cyg first photoelectric observation (1962). Old photographic
V1073 Cyg observations give the impression of the sinusoidal period change.
EF    Dra Third component spectroscopically detected. Possible variation in the
EF    Dra (O-C) diagram. Object discovered as an X-ray source.
UX    Eri Irregular period variation.
YY    Eri Sinusoidal variation seen in the (O-C) diagram interpreted as
YY    Eri continuous mass transfer combined with LITE or cyclic magnetic
YY    Eri activity. Abrupt period changes are another possibility.
AK    Her The brighter component of the visual double ADS10408.
AK    Her Separation 4.7". Quasi-sinusoidal period variation with two or more
AK    Her periodicities.
DF    Hya Period increase since the beginning of the observations (1935) with
DF    Hya mean (dP/dt)/P=+4.24*10^-7^year^-1^ or abrupt period increase
DF    Hya {Delta}P/P=+1.76*10^-5^ around 1965.
EZ    Hya Fast period decrease since the beginning of the photoelectric
EZ    Hya observations (1969) with mean (dP/dt)/P=-1.46*10^-6^year^-1^.
EZ    Hya The (O-C) residuals deviate from the parabolic representation.
SW    Lac Presence of two other components in the systems seen in the (O-C)
SW    Lac diagram with 23 and ~90 years orbital periods. Multiplicity of the
SW    Lac system confirmed by spectroscopic observations.
XY    Leo Multiple system. The third component on a P~20 years orbit is a
XY    Leo BY Dra binary with an orbital period 0.805 days.
AM    Leo The brighter component of the visual double ADS 8024.
AM    Leo Separation 11.3". Possible presence of a third body indicated by the
AM    Leo sinusoidal variation (P~33 years) seen in the (O-C) diagram.
V502  Oph A third body detected spectroscopically. A continuous decreaseand a
V502  Oph probable sinusoidal oscillation with a period of 35yr in the (O-C)
V502  Oph diagram.
V566  Oph Abrupt period increase (dP/dt)/P=+1.41*10^-5^ around 1972. Latest
V566  Oph (O-C) residuals deviate from the linear representation.
V839  Oph Orbital period seems to be modulated by more than one mechanism.
ER    Ori Member of a multiple system. The brighter component of
ER    Ori IDS05065-00840. Separation 13.6". Another component detected by
ER    Ori speckle interferometry 0.19" distant. Complicated (O-C) diagram.
BX    Peg Period decrease since the beginning of the observations (1926) with
BX    Peg mean (dP/dt)/P=-2.38*10^-7^year^-1^. Since 1986 period seems to be
BX    Peg approximately constant.
AU    Ser Abrupt period decrease {Delta}P/P=-1.49*10^-5^ around 1988.
RZ    Tau Variable period increase since the beginning of the observations
RZ    Tau (1916) with mean (dP/dt)/P=+2.37*10^-7^year^-1^.
AH    Tau Abrupt period decrease {Delta}P/P=-1.17*10^-5^ around 1974. The (O-C)
AH    Tau residuals before the change deviate from the linear representation.
EQ    Tau Possible third body (P~50 years) indicated by the course of the (O-C)
EQ    Tau residuals.
W     UMa Complicated quasi-periodic change of the period since the beginning
W     UMa of the observations (1902).
TY    UMa Period increase since the beginning of the observations (1933) with
TY    UMa mean (dP/dt)/P=+7.13*10^-7^year^-1^ or two abrupt period increases,
TY    UMa the second around 1981.
AW    UMa Variation seen in the (O-C) diagram interpreted as LITE or two abrupt
AW    UMa period decreases. The presence of a third body indicated by the
AW    UMa systemic velocity changes.
AH    Vir The brighter component of a visual double ADS 8472 with ~1280 years
AH    Vir orbit. Presence of a third body on a 11.2 years orbit seen in the
AH    Vir (O-C) diagram.