1. Are the rules of EU law on the determination of the applicable legislation in the area of social security according to Regulation (EC) No 883/2004 in conjunction with Regulation (EC) No 987/2009 to be applied to a situation in which an EU citizen is simultaneously self-employed in an EU State, an EEA EFTA State (Liechtenstein) and Switzerland.

If the answer to the first question is in the affirmative:

2. Must the application of Regulation (EC) No 883/2004 in conjunction with Regulation (EC) No 987/2009 in such a case be such that the applicability of the social security legislation must be assessed separately in the relationship between the EU Member State and the EEA-EFTA State, on the one hand, and the relationship between the EU Member State and Switzerland, on the other hand, and must, accordingly, a separate certificate regarding the applicable legislation be issued in each case?

3. Is there a change in the ‘relevant situation’ within the meaning of Article 87(8) of Regulation, (EC) No 883/2004 where a self-employment activity is commenced in another State to which the said regulation is applicable, even if a change in the applicable legislation would not result either under Regulation (EC) No 883/2004 or under Regulation (EEC) No 1408/71 and the activity is so subordinate in extent that only about 3% of total income is thereby obtained?

4. In that regard, does it make any difference whether, within the meaning of the second question, coordination in bilateral relations must take place separately, that is to say, on the one hand, between the States hitherto concerned and, on the other hand, between one of the States hitherto concerned and the ‘other’ State?