Books and journals which compare and contrast more than one national jurisdiction are in separate sections of the Law Bod, indicated by shelf marks starting General, Cw Gen or KB. All the current monographs are on Level 2, the level you enter the libary. Journals 2000 and onwards on Level 1, and 1999 and earlier on the Ground Floor.
These links may help you find online criminal codes from other countries: the texts should be reliable, but will not be authoritative (especially if it is an English translation)
The Law Bod has a number of Libguides to foreign jurisdictions each of which will have sections on where to find the nation's legislation.
KM has works not just on English & Welsh criminal law but also on the laws of other common law jurisdictions. The third line of the shelf mark is the key to understanding which jurisdiction is being considered:
A8 is Australia, C1 Canada, I5 Ireland, N4 New Zealand, S3 Scotland, and U4 United States of America.
Other foreign jurisdictions have shelf marks beginning with their country's name eg France for French law, Cw India for Indian etc.
The Law Bod has published a number of guides giving guidance on where to find law and commentary from legal systems other than England & Wales, & we have a number of Libguides for a number of them. Pleases follow any relevant links vi Resources for Jurisdictions
The European Journal of Criminology (see link below) includes a 'country survey' of a selected country within the wider Europe (the EU and beyond). Country surveys summarize essential facts about the criminal justice system, review trends in crime and punishment, and discuss major publications in recent years.
The websites of various organisations may make available useful collections of relevant legislation and/or case law in this area of law. Do be aware of the date of any source collected: you may well need to check whether threre has been any amendments or new legislation, or subsequent court decisiions. In some instances they provide translations into English (or English summaries). Any such translations are unofficial.