@Override
	public String toString() {
		int i;
		StringBuilder sb = new StringBuilder();

		if (this.getMarks() != null) {
			try {
				if (average() != 0) {
					sb.append(super.toString());
					sb.append("\n\tPromotion: " + p.getName());
					sb.append("\n\tId: ").append(id).append("\n\tMarks: ");

					for (i = 0; i < NB_EVALUATIONS; i++) {
						if (this.marks[i] != null) {
							sb.append(marks[i] + " ");
						}
					}

					sb.append("\n\tGrader(s): ").append(this.getGraders());
					sb.append("\n\tAverage: ").append(this.average())
							.append("\n");
				}
			} catch (EmptyMarks e) {
				System.out.println(super.toString() + " doesn't have marks !");
			}
		}
		return sb.toString();
	}