# The “number” symbol refers to entries in Volume II (Marx–Engels Register), in conjunction with “ME,” “M,” or “E.” For example, #ME74 = Marx and Engels' Holy Family; #M129 = Marx's Capital; #E23 = Engels' Anti–Dürhing; etc.

* The hyperlink standing alone refers only to the entries in Volume III (Marx–Engels Glossary). Marking a name (person, periodical, etc.), it means that there is an entry for this name in the Glossary; it is used only when there is special reason to signal the entry.

+ The plus symbol following a date means indefinite continuance; e.g., 1834+ means “From 1834 on. . . .“

/ The solidus or slash mark generally means “or,” as in “M/E” (Marx or Engels). Similarly, “1834/35” means “1834 or 1835.“

% The percent sign, used in Volume II (Marx–Engels Register), indicates a partial translation.

+ + The double plus sign, used in Volume II (Marx–Engels Register), indicates additional information or notes.

Parts of the Month: In the absence of exact information, parts of the month may be indicated using the letters A, B, C, and D to stand for the four quarters of the month. For example,

Mar A = beginning of March

Mar AB = first half of March

Mar M = middle of March

Mar CD = last half of March

Mar D = end of March

“About” Dates: Before a date or its symbol, the word about may be represented by “c.” (for “circa”). For example,

Mar c.7 = about Mar 7

c.1853 = about 1833

Mar c.A = about the beginning of March 

Mar c.CD = about the last half of March 

But the common abbreviation “ca.” (also for “circa”) may be used with the same meaning in other circumstances.

The letters M and E (without periods) are often used for the names Marx and Engels, especially in concise presentations of information; ME = Marx and Engels (in Register titles), M–E = Marx and Engels (in certain other contexts), M/E = Marx or Engels.