Accordingly, the situation across the different countries varies considerably.  For example, in countries such as Norway, Finland and the Netherlands, which have only consultative referendums, obviously the only type of referendum that could be held in this respect would be a consultative one.  In Portugal, where referendums cannot relate to constitutional provisions, no such popular vote could be held, even if the provision in question concerned referendums.  In contrast, in Switzerland, where the constitution is subject to mandatory referendum and legislation to optional referendum, any provision relating to referendums (except where it is regulatory) must, under the law, be submitted to referendum.  Between these two extremes, every possible situation is to be found.  Clearly, in countries where constitutional amendments are subject to mandatory referendum (in addition to Switzerland, this is also the case in Andorra, Armenia, Azerbaijan, Denmark and Ireland), this also applies where such amendments relate to referendums.  In Italy, constitutional provisions are submitted to suspensory referendum and legislation to abrogative referendum at the request of 500,000 voters. In Albania, constitutional provisions relating to referendums (like all other constitutional provisions) may not be amended without a referendum unless they have been approved by a two thirds majority in parliament.