This is not currently part of the peer-reviewed material of the project. Do not cite as a research publication.
Use the following codes in regular expression searches.
|^||match the beginning of a field|
|$||match the end of a field|
|.||match any character|
|\.||match a full-stop|
|a*||match any sequence of zero or more a characters|
|a+||match any sequence of one or more a characters|
|a?||match either zero or one a character|
|de|abc||match either of the sequences de or abc|