Taking Notes
Players are allowed to take written notes during a match and may refer to those notes while that match is in progress. At the beginning of a match, each player’s note sheet must be empty and must remain visible throughout the match. Players do not have to explain or reveal notes to other players. Judges may ask to see a player’s notes and/or request that the player explain his or her notes.
Players may not refer to other notes, including notes from previous matches, during games.
Between games, players may refer to a brief set of notes made before the match. They are not required to reveal these notes to their opponents. These notes must be removed from the play area before the beginning of the next game. Excessive quantities of notes (more than a sheet or two) are not allowed and may be penalized as slow play.
The use of electronic devices to take and refer to notes is permitted at Regular Rules Enforcement Level (see section 2.12 – Electronic Devices).
Players and spectators (exception: authorized press) may not make notes while drafting. Players may not reference any outside notes during drafting, card pool registration, or deckbuilding.
Players may refer to Oracle text at any time. They must do so publicly and in a format which contains no other strategic information. Consulting online sources, such as gatherer.wizards.com, is allowed at Regular Rules Enforcement Level even if they contain a small amount of strategic information. If a player wishes to view Oracle text in private, he or she must ask a judge.
Artistic modifications to cards that indirectly provide minor strategic information are acceptable. The Head Judge is the final arbiter on what cards and notes are acceptable for a tournament.

Electronic Devices
At Competitive and Professional Rules Enforcement Level during drafting, deck construction, and playing of matches, players may not use electronic devices capable of taking and storing notes, communicating with other people, or accessing the internet (with the exception of taking brief personal calls with the opponent's permission).
At Regular Rules Enforcement Level, electronic devices are permitted, but players may not use them to access information that contains substantial strategic advice or information about an opponent's deck. Device use during a match other than brief personal calls must be visible to all players. Players wishing to view information privately on electronic devices during matches must request permission from a judge.
The Head Judge or Tournament Organizer of a tournament may further restrict or forbid the use of electronic devices during matches.

Excessive quantities of notes (more than a sheet or two) are not allowed and may be penalized as slow play.

comme ça tu es fixé sans la moindre ambiguïté.

ça laisse une liberté d'interprétation tout de même...