Question: What British games manufacturer publishes "White Dwarf," a magazine which gave Dragons of Mystery a middling review?

Context paragraphs:
Pulsating white dwarf: A pulsating white dwarf is a white dwarf star whose luminosity varies due to non-radial gravity wave pulsations within itself.  Known types of pulsating white dwarfs include DAV, or ZZ Ceti, stars, with hydrogen-dominated atmospheres and the spectral type DA; DBV, or V777 Her, stars, with helium-dominated atmospheres and the spectral type DB; and GW Vir stars, with atmospheres dominated by helium, carbon, and oxygen, and the spectral type PG 1159.  (Some authors also include non-PG 1159 stars in the class of GW Vir stars.)  GW Vir stars may be subdivided into DOV and PNNV stars; they are not, strictly speaking, white dwarfs but "pre-white dwarfs" which have not yet reached the white dwarf region on the Hertzsprung-Russell diagram.  A subtype of DQV stars, with carbon-dominated atmospheres, has also been proposed., and in May 2012, the first extremely low mass variable (ELMV) white dwarf was reported.

Dragons of Mystery: Dragons of Mystery is a "Dungeons & Dragons" sourcebook published in 1984 as part of a series of modules for the "Dragonlance" (DL) campaign setting.  It is the fifth of fourteen Dragonlance modules published by TSR between 1984 and 1986.  Its cover features a painting by Larry Elmore of the characters Tanis Half-Elven, Laurana Kanan, Tasslehoff Burrfoot, and Tika Waylan standing in front of a dragon highlord and a blue dragon.  The sourcebook received middling reviews from "White Dwarf" magazine.

White dwarf: A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter.  A white dwarf is very dense: its mass is comparable to that of the Sun, while its volume is comparable to that of Earth.  A white dwarf's faint luminosity comes from the emission of stored thermal energy; no fusion takes place in a white dwarf wherein mass is converted to energy.  The nearest known white dwarf is Sirius B, at 8.6 light years, the smaller component of the Sirius binary star.  There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun.  The unusual faintness of white dwarfs was first recognized in 1910.  The name "white dwarf" was coined by Willem Luyten in 1922.

Van Maanen 2: Van Maanen 2 (van Maanen's Star) is a white dwarf.  It is a dense, compact stellar remnant that is no longer generating energy, having about 68% of the Sun's mass but only 1% of the Sun's radius.  Out of the white dwarfs known, it is, at 13.9 light-years, the third closest to the Sun, after Sirius B and Procyon B, in that order, and the closest known solitary white dwarf.  Discovered in 1917 by Dutch–American astronomer Adriaan van Maanen, Van Maanen 2 was the third white dwarf identified, after 40 Eridani B and Sirius B, and the first that was not a member of a multi-star system.  A spectrographic plate made in 1917 shows evidence of planetary matter around the star.

Intermediate polar: An Intermediate Polar (also called a DQ Herculis Star) is a type of cataclysmic variable binary star system.  In most cataclysmic variables, matter from a main-sequence companion star is gravitationally stripped by a white dwarf star and forms an accretion disk around the white dwarf.  In intermediate polar systems, the same general scenario applies, except that the inner disk is truncated by the magnetic field of the white dwarf.  In extreme instances, the disk can be fully disrupted, although this is uncommon.  In the region where the disk is truncated, the gas in the disk begins to travel along the white dwarf's magnetic field lines, forming curved sheets of luminous material called "accretion curtains".  Disk material passes through the curtains and then accretes onto the white dwarf near one of its magnetic poles.

RR Caeli: RR Caeli is a double star in the constellation Caelum.  It is approximately 66 light years from Earth.  It was first noted to be a high-proper motion star in 1955 by Jacob Luyten, and given the name LFT 349.  Discovered to be an eclipsing binary in 1979, it has a baseline magnitude of 14.36, dimming markedly every 7.2 hours for an interval of around 10 minutes, due to the total eclipse of the brighter star by the fainter one.  Its variability in brightness led to its being given the variable star designation RR Caeli in 1984.  This star system consists of a red dwarf of spectral type M6 and a white dwarf that orbit each other every seven hours; the former is 18% as massive as the Sun, while the latter has 44% of the Sun's mass.  The red dwarf is tidally locked with the white dwarf, meaning it displays the same side to the heavier star.  The system is also a post-common-envelope binary, and the red dwarf star is transferring material onto the white dwarf.  In approximately 9–20 billion years, RR Caeli will likely become a cataclysmic variable star due to the period's gradual shortening, leading to increasing rates of transfer of hydrogen to the surface of the white dwarf.

RS Ophiuchi: RS Ophiuchi ("RS Oph") is a recurrent nova system approximately 5,000 light-years away in the constellation Ophiuchus.  In its quiet phase it has an apparent magnitude of about 12.5.  It has been observed to erupt in 1898, 1933, 1958, 1967, 1985, and 2006 and reached about magnitude 5 on average.  A further two eruptions, in 1907 and 1945, have been inferred from archival data.  The recurrent nova is produced by a white dwarf star and a red giant in a binary system.  About every 20 years, enough material from the red giant builds up on the surface of the white dwarf to produce a thermonuclear explosion.  The white dwarf orbits close to the red giant, with an accretion disc concentrating the overflowing atmosphere of the red giant onto the white dwarf.

AR Scorpii: AR Scorpii (AR Sco) is a binary pulsar that contains a white dwarf and a red dwarf.  It is the first "white dwarf-pulsar" to be discovered.  The 3.56-hour period in AR Sco's light curve caused it to be misclassified as a Delta Scuti variable, but in 2016, this period was found to be the binary orbital period.  In addition, the system shows very strong optical, ultraviolet, and radio pulsations originating from the red dwarf with a period of just 1.97 minutes.  These pulsations occur when a relativistic beam from the white dwarf sweeps across the red dwarf, which then reprocesses the beam into the observed electromagnetic energy.  At present, the white dwarf is not accreting significantly, and the system is powered by the spin-down of the white dwarf.  The pulsar is about the same size as Earth.

White Dwarf (magazine): White Dwarf is a magazine published by British games manufacturer Games Workshop, which has long served as a promotions and advertising platform for Games Workshop and Citadel Miniatures products.

Battle Games in Middle-earth: Battle Games in Middle-earth (BGiME) was a fortnightly magazine published by De Agostini in conjunction with British games manufacturer Games Workshop.  Unlike "White Dwarf", which is dedicated to the three core systems of miniature wargaming produced by Games Workshop, "BGiME" was exclusively about "The Lord of the Rings Strategy Battle Game".

Supporting paragraphs: Dragons of Mystery White Dwarf (magazine)
Answer: Games Workshop