Swedish has quite a peculiarity that I haven't found (yet) in other languages. There are some spellings that are pronounced all the same way. Currently the number of these spellings is disputed, but it seems that a minimum list was compiled. From this section in the Swedish Alphabet wikipedia article:
Garlén (1988) gives a list of 22 spellings (⟨ch⟩, ⟨che⟩, ⟨g⟩, ⟨ge⟩, ⟨gi⟩, ⟨ige⟩, ⟨j⟩, ⟨je⟩, ⟨sc⟩, ⟨sch⟩, ⟨sh⟩, ⟨shi⟩, ⟨si⟩, ⟨sj⟩, ⟨sk⟩, ⟨skj⟩, ⟨ssi⟩, ⟨ssj⟩, ⟨stg⟩, ⟨sti⟩, ⟨stj, ⟨ti⟩), but many of them are confined to only a few words, often loan words, and all of them can correspond to other sounds or sound sequences as well.
But like I said others say the list is much longer. Not only the number is under a dispute, however, since also the classification of the sound itself is "under fire".
From the Wikipedia article about the Sj-sound, represented with the IPA /ɧ/, has many classifications. From the same article:
The International Phonetic Association describes [ɧ] as "simultaneous [ʃ] and [x]", but this claim is disputed among phoneticians, including at least one former president of the IPA. Other descriptive labels include voiceless palatal-velar fricative, voiceless dorso-palatal velar fricative, voiceless postalveolar and velar fricative, or voiceless coarticulated velar and palatoalveolar fricative. The closest English phoneme is /ʃ/ ⟨sh⟩.
What is the current situation? In other words, was a consensus reached? I understand this is hard, but who knows. Also, what are the most important papers/resources about this topic?