Turkey is voting on Sunday in a referendum on key constitutional changes seeking to transform the country's governance from a parliamentary system to an executive presidency, significantly expanding the powers of the top office.

Here are four must-read pieces looking at what is at stake in this crucial vote which will have big implications for Turkey's future. 

How will Turkey change if it votes 'Yes'?  

President Recep Tayyip Erdogan and the ruling Justice and Development Party (AK Party) argue that an executive presidency will make Turkey more stable.

Opposition parties, led by the Republican People's Party (CHP), say that the changes will create a "one-man rule" by degrading democratic institutions and the separation of powers in the country.

Go here to see our interactive on how Turkey's political system will change if it votes "Yes".

Supporters of Turkish President Recep Tayyip Erdogan at a "Yes" campaign rally [Alkis Konstantinidis/Reuters]
The two sides of the debate  

Al Jazeera spoke to leading figures on different sides of the argument over the proposed changes.

Ibrahim Kalin, Erdogan's spokesperson, told Al Jazeera why he believes a "Yes" vote is essential to safeguard Turkey's future:

"[The Turkish people] understand that we cannot defend our democracy against attacks if we do not take certain steps right now," said Kalin.

But Sezgin Tanrikulu, a senior CHP MP, argued that a "No" vote was needed to protect democracy:

"If you try to impose one colour, one man's rule, to this colourful place, the problems will deepen," said Tanrikulu.

Turkey's constitutional reform: All you need to know  

Al Jazeera's Birce Bora identified the key issues at stake in the referendum and spoke to several experts to get to the heart of the proposed changes that aim to fundamentally change how Turkey is governed.

'Hayir' - 'No' - supporters at a referendum campaign rally in Istanbul [Murad Sezer/Reuters]

Vox-pops: Turkish voters weigh in before referendum  

Al Jazeera's Umut Uras heard from "Yes" and "No" voters about their motivations, hopes and fears in the referendum.

A "Yes" voter shared her views on the current constitution that the proposed changes are seeking to alter:

"Our constitution is a stiff text made by a military junta who does not understand the language of the people."

One "No" voter spoke about her fears if the referendum is passed:

"I am going to vote 'No' in the referendum, because I want to live in a republic, not a monarchy. Turkey will lose its democracy if these changes are passed."

Source: Al Jazeera News