Perhaps, by "mnemonic formulas" the author meant something else. The most useful mnemonic techniques for memorizing a large amount of information (poems, numbers, words) are well described in Foer Joshua's book "Einstein walks on the moon" (I advise). Basically, these are, of course, so-called "palaces of memory".
More specifically, here is a good technique for memorizing dates:
Each digit corresponds to a letter (0-s, 1-dpi, 2-n, 3-m, 4-r, 5-l, 6-sh / h, 7-c / d, 8 -w / f, 9-b / p). You need to learn them.
We take any date, for example, the calling of the Vikings to Russia (862). In letters it will look like "vshn" (you could have used f and h, but here it is good without them). From this "vshn" we come up with a word, the first thing that comes to mind is "height" (well, or the top).
Draw the following picture as vividly as possible - a ship sails from across the sea with Rurik and brothers on board. They go ashore, where they are greeted by representatives of the tribes and together they climb to the nearest top (!) Of the hill in order to look at the future possessions. The more detailed the picture is in your imagination (weapons, clothes, facial expressions, wet land of the hill), the better everything will be remembered. Now, at the mention of the calling of the Varangians, this picture with a hill will immediately appear in your head and the date will immediately pop up.
(my girlfriend suggests that it would be better if they gobbled on cherries, this image is much brighter than the top)
Every hunter wants to know where the pheasant is sitting.
How once Jacques the city bell ringer cut down a lantern.
This is about the rainbow.
Let's continue the topic of anatomy:
Like lyamin cribrosa
Crista gali settled.
Foramen tsecum ahead,
Behind - os sphenoidale.
This is about the skull.
Wake up, the sinister undertaker is raging the tone of the body, depriving his own tongue of an immense share of pessimism - the first letters are the cranial nerves (olfactory, visual, oculomotor, block, trigeminal, abductor, facial, auditory, glossopharyngeal, wandering, additional, sublingual).
Verbs not from their conjugation (probably :): See, Hear and Look. Breathe, Hold, Still Twirl. Endure, Depend, Drive, Hurt, and last. To hate.
Ivan gave birth to a girl, ordered to drag the diaper. - Cases.
The first thing that came to mind.
As on a boat in the moonlight, three ate peas, but removed the fish heads from the hook and folded a trapezoidal trapezoid - to memorize the bones of the wrist (scaphoid, lunate, triangular, hooked, capitate, trapezoidal, trapezoid)
UMRU - a diagram of the innervation of the hand by the radial, medial and radial nerves.
And I forgot all the other mnemonic rules, alas.
(We need 20 more characters)