diff --git a/docs/references/functions.md b/docs/references/functions.md
index d79f8bc5..7db5ea52 100644
--- a/docs/references/functions.md
+++ b/docs/references/functions.md
@@ -27,7 +27,7 @@ Available through the _ExpressionConfiguration.StandardFunctionsDictionary_ cons
 | NOT(value)                                                                | Boolean negation, implemented as a function (for compatibility)                                                                                 |
 | RANDOM()                                                                  | Produces a random value between 0 and 1                                                                                                         |
 | ROUND(value, scale)                                                       | Rounds the given value to the specified scale, using the current rounding mode                                                                  |
-| SQRT(value)                                                               | Square root function                                                                                                                            |
+| SQRT(value)                                                               | Square root function. Uses the implementation from _The Java Programmers Guide To numerical Computing_ by Ronald Mak, 2002.                     |
 | SUM(value, ...)                                                           | Returns the sum of all parameters. If a parameter is of type _ARRAY_, the sum of all elements is calculated.                                    |
 | SWITCH(expression, value1, result1, [value2-N, result2-N ...], [default]) | Returns the _result_ correponding to the first matching _value_ in the specified _expression_ or an optional _default_ value if no match found. |
 
diff --git a/src/main/java/com/ezylang/evalex/functions/basic/SqrtFunction.java b/src/main/java/com/ezylang/evalex/functions/basic/SqrtFunction.java
index ffe4ecc7..8662bb23 100644
--- a/src/main/java/com/ezylang/evalex/functions/basic/SqrtFunction.java
+++ b/src/main/java/com/ezylang/evalex/functions/basic/SqrtFunction.java
@@ -24,7 +24,10 @@
 import java.math.BigInteger;
 import java.math.MathContext;
 
-/** Square root function, uses the standard {@link BigDecimal#sqrt(MathContext)} implementation. */
+/**
+ * Square root function, uses the implementation from <i>The Java Programmers Guide To numerical
+ * Computing</i> by Ronald Mak, 2002.
+ */
 @FunctionParameter(name = "value", nonNegative = true)
 public class SqrtFunction extends AbstractFunction {
 
@@ -34,8 +37,9 @@ public EvaluationValue evaluate(
 
     /*
      * From The Java Programmers Guide To numerical Computing
-     * (Ronald Mak, 2003)
+     * (Ronald Mak, 2002)
      */
+
     BigDecimal x = parameterValues[0].getNumberValue();
     MathContext mathContext = expression.getConfiguration().getMathContext();