Motorola published the Zener Diode Handbook, 1st edition in 1967, it had a lot of information on zeners and using them. Some years later, Motorola republished the handbook but I do not consider it to be as good as the original (I have both of them). These books have become difficult to find and while they are probably available in PDF form somewhere (ON Semi), they were not meant to be precision voltage references with the exception of certain types:
The old 1N827/A voltage reference zener which dates back to the 1950s from Motorola, this special zener could exhibit a TCV of 5 PPM/°C but this wasn't the only Motorola zener that could do that; the 1N4569/A, 1N4574/A, 1N4579/A, 1N4584/A, 1N4779/A, 1N4784/A, 1N939/A/B, 1N4769/A, 1N4774/A, 1N2624/A/B, 1N2169/A, 1N2170/A, 1N2171A and the 1N945/A/B. These zeners all had 5 PPM/°C TCV and voltages between 6.2V and 11.7 V nominally. The zener currents varied between 0.5mA and 10mA for best performance and the temperature extremes could be as wide as -55°C and +150°C, pretty impressive I'd say.
Some of these diodes may still be available.