Madhyamaka, Mādhyamaka, Madhyamika, Mādhyamika? Two spelling/usage questions about two Sanskrit words common in Buddhism.

First, what is the difference between Madhyamaka (ending in "aka") and Madhyamika (ending in "ika"). I have seen that the former is the doctrine or school while the latter is an adherent of that school. Is that correct?

Second, are either or both properly rendered in the Latin alphabet with or without the straight bar diacritical over the initial a: Madhyamaka or Mādhyamaka; Madhyamika or Mādhyamika.

I have seen it both ways in numerous contexts.
From Wikipedia:


  Madhya is a Sanskrit word meaning "middle" ... The -ma suffix is a superlative, giving madhyama the meaning of "mid-most" or "medium". The -ka suffix is used to form adjectives, thus madhyamaka means "middleling". The -ika suffix is used to form possessives, with a collective sense, thus mādhyamika mean "belonging to the mid-most" (the -ika suffix regularly causes a lengthening of the first vowel and elision of the final -a).  
  
  In a Buddhist context these terms refer to the "middle path" (madhyama pratipada) between the extremes of annihilationism (ucchedavāda) and eternalism (śassatavāda), for example:  
  
  Kātyāyana Sūtra: Thus, the Tathāgata teaches the Dharma by a middle path avoiding both these extremes.  
  
  
  Madhyamaka refers to the school of thought associated with Nāgārjuna and his commentators.  
  Mādhyamika refers to adherents of the Madhyamaka school.  
  
  
  Note that in both words the stress is on the first syllable.


So if we are to believe this, it looks like "madhyamaka" with a short "a" is the middle path school, and "mādhyamika"s with a long "a" are its followers.